There are things I only worked out how to do in Fallout 4 [official site] after hours and hours of play, so I thought I'd spare the rest of you from similar confusion. From fuss-free shopping to streamline construction and power armour management, and of course figuring out how to run those blasted settlements, here are a few must-know pieces of hard-earned wisdom. Some apply to total greenhorns, some might surprise even people fairly deep into the game - and I'll add to them as more occur.
I can't quite decide if the game just got itself into a bit of a muddle when it comes to explaining its many, many less than obvious systems or if it truly has a sink or swim philosophy, figuring that it's far more satisfying for players to work everything out for themselves. I suspect the former, to be honest, given its many other glitches and that most of the features it fails to document are down to user interface obfuscation (and a complete absence of relevant tutorial) rather than delightful things one might stumble across through experimentation. (Although I include a couple of those too).
1) How to use the Perk menu
This comes under the category of stuff for near-newbies. That Perks unlock screen in the Pipboy? Looks as though it's just a single screen, doesn't it? No arrows, no scrollbars, no prompts- but in fact it scrolls way down, revealing a whole mess of other perks, including the arguably vital likes of Lockpicking and Science, plus returning favourite Bloody Mess. Right-click and drag to move around it, or alternatively move the cursor to the edge of the screen. You can also pointlessly zoom in and out a tiny bit with the mouse wheel. Sadly there are no ways to organise or filter it to be more easily-browsed.
2) How to find your Power Armour
You can't shove a suit of Power Armour in a cupboard, so what to do with it if you're running out of Fusion Cores or simply want to stroll around in your civvies for a while? Well, just get out of it and leave it wherever - and a new icon will appear on the map showing where you've left it.
3) How to repair Power Armour
If you do wear Power Armour regularly, you'll notice that, unlike regular armour, it can get pretty messed up, even to the point that you can't wear it any more. You'll want to repair it regularly, which you can do by walking close to a Power Armour Station - the yellow upright frames which look like a partially-dismantled Aliens powerloader - getting out of the armour and then hitting Use on the Station (E by default). Repair and upgrade options should then pop up. Keep a lot of Steel around for repairs, by the way.
4) Easy junk storage
And while we're talking about crafting stations, did you know that you can store stuff in them? If there's somewhere you visit frequently, the stations make an easy and logical place to leave items you don't need with you at all times. This is doubly useful in terms of junk; I know I spent a few too many hours hauling around a backpack full of toasters and microscopes because I was worried I'd forget which shelf or trunk I'd stuck them all in otherwise. There's even a shortcut to dump all Junk - i.e. everything that isn't a weapon, armour, aid or quest item - into a crafting station. Just press R to enter Transfer mode (not E to Use) then T the shift all junk over.
5) Making more space in settlements
Speaking of Settlements, there are a couple of less than obvious tricks worth knowing about. The first two you probably did work out by yourself, but I'll stick 'em here for the record. One is that you scan scrap a great deal of existing crap in settlements - lamposts, beds, rusted cars, even some derelict buildings - by pressing R while in build mode. This reduces them to a few components parts - usually steel and wood - and dumps it directly into the the settlements' storage. (You can access this storage from a crafting station, as described above. You can also network crafting stations between settlements - see tip 8). You can also do this to useful and decorative stuff, and also to any weapons or armour - though they require either doing it from a crafting station or by manually dropping the item in question on the ground then entering build mode and doing the R to scrap thing.
6) Moving and storing existing furniture and crafting stations
Secondly, you can relocate or store intact existing furniture and stations that you want to keep. Go into build mode, hover the reticule over the item in question and press E to select it, which lets you move it around, or Tab to send it into storage. This means you can access it from elsewhere without having to build a brand new whatever it is.
7) How to assign roles to settlers
Thirdly and most importantly/least obviously, if you're anything like me you'll have been frustrated about how to assign settlers to tasks such as farms and defences. Sometimes a new settler will walk up to you and ask if there's anything they can do, but if you miss the prompt that's it, they'll never ask again and will just hang around like a bad, useless smell. What you really have to do is enter Build mode, go hover the reticule over a settler and press E - you can then tell the settler to walk somewhere, or point the reticule at a construction and you can assign them to it. No more withered Tato plants.
8) How to share storage across all settlements
This Settler assignation function serves an extra, perhaps even more useful purpose - you can use them to essentially network crafting stations, so anything you've stored in them becomes accessible from any of your settlements. No more repeatedly hoofing it between Sanctuary Hills to Red Rocket because you haven't got quite enough fuses in one place, in other words. You'll need to have unlocked the Local Leader perk for this, which itself requires a Charisma of 6. With that done, repeat the build mode / find spare settler process above, but press Q to activate a Supply Line rather than E to Command - you'll then be presented with a list of settlements. Choose one to form a link between it and your current location. Note that this will essentially remove the settler from the current place's population, however, as well as dragging them off any other task they might have been associated with. It's also worth nothing that you can also assign some companions to Supply Lines, if you're short on spare settlers.
9) Where to get free Fusion Cores
I suspect this falls into the 'sanctioned cheat' category, as it's also a cheery little semi-emergent experiment. If you're doing the whole Power Armour thing, your most precious resource is Fusion Cores, those little glowing pucks which give your metal suit its defensive and mobile capabilities. You can find these hidden deep inside some buildings, and occasionally for sale at exorbitant prices - but the best way to get hold of them is from the Brotherhood Of Steel. If you won't or can't sign up with the big ol' stern techno-fascists, how about stealing cores from them?
You don't have to become their enemy to do this - just get your pickpocket perk up to 3 then keep your eyes peeled for suited'n'booted Brotherhood troops. Sneak up on them and you can steal the Fusion Core right out of the back of the suit. One hell of a design flaw if you ask me, especially as this then prompts the soldier to pop out of his now semi-non-functional suit and leave it right there, so you can then rob limb, torso and helmet armour upgrades from it. Or even the whole suit, if you've not bought one yet. If you're enemies with the Brotherhood, this is also a powerfully effective strategy - sneak up, take the core and make them hatch out of their protective shell before you start fighting.
10) How to filter items while trading
A quick general shopping tip. Easy and vital when you know how, a massive pain in the wobbly bits if you don't. When trading, you can switch between categories (i.e. weapons, apparel etc) rather than have to endlessly scroll through a long list which initially seems as though it can only be sorted alphabetically, by damage, value or weight. Just look for the little arrows to the left and right of 'My Inventory' or the trader's name and you can cycle through the categories. If those arrows aren't there - as they're often not - you can click anyway and it will still cycle through. Saves a lot of legwork, this.
11) How to holster your weapon
Most people who played Skyrim or Fallout 3 will probably know this already, but it bears repeating for total greenhorns - hold down R (or whatever reload is bound to) to put your weapon away. As well as very occasionally making NPCs more amenable, having your screen clear of a honking great gun means you can see more of what's going on, helps get into the roleplay spirit in towns and makes for cleaner screenshots.
12) Easy experience points
You get experience points from every kind of crafting, in addition to combat and quests. So visit science and cookery stations often to see what you can do with whatever crap is hanging around your inventory. Be it cooking scorpion meat or mixing drugs together, there's usually some recipe you can fulfill, and after a long time in the wilderness you might find you get a big splurge of experience for it.
13) The importance of casual wear
Charisma doesn't just affect your chances in quest-based dialogue and unlock new Perks - the more charming you are, the better the rate you get from traders, for both buying and selling. So don't turn your nose up at all those sequin dresses and tatty suits with no armour rating but +2 Charisma - stick 'em on when shopping and you'll save a pretty penny. The same's true of the Day Tripper drug, which I guess is post-apocalyptic cocaine, though be wary of addiction or seeming like you work in the music industry.
14) Shoot from cover
There is a cover system of sorts. If you stand at the edge of a building/wall or behind an open door, you'll notice that you can't see past it. Unless you hit right click (or whatever you have assigned to sighted mode), at which point your character will automatically lean out and have a clear shot from relative safety. Bear in mind this only works while in first-person mode, however - in third person, you'll just see whatever's directly in front of you, which usually means whatever bit of brick or wood you're skulking behind.
15) Companion inventories and appearance
You can dress up some Companions - in fact they can wear anything you can, power armour aside, and the same's true of weapons. Talk to them, ask to trade, then send whatever items you want them to wear or carry over to the inventory. Select it (from the right-hand pane) and press T, and you'll see it reflected in their appearance immediately. This is great both for co-ordinating outfits and making your chum of chums more combat-effective. Note that this broadly only works for human companions - although Dogmeat-specific armour can occasionally be found or bought.
There are more things like this. There will be still more things like this. Please share suggestions and questions alike below and I'll update this with anything else that seems useful.