RE: Warlock: Fatal Bonds should be used as much as possible when enemy heroes get near the creep line to harass them. They will likely start to play more passively as a result; only put one point in this skill (ideally at level 2) to prevent it from pushing the lane too hard. Shadow Word is incredibly inefficient in terms of mana cost at level 1, so try to hold off on using it until you have another level in it. It's generally best to save Shadow Word to heal your lanemate, but if you have an urn throwing down both DoTs can be very effective on a fleeing enemy. Upheaval is quite simply one of the best slows in the game. In a team fight, you'll want to throw down Fatal Bonds, Ult, and your ultimate as quickly as possible. This will prevent heroes with blink daggers from escaping your slow thanks to the Golem's Immolation. Try to keep your Golem alive with Shadow Word, as it gives a large bounty if the enemy heroes score a last hit on it.

Because your heal is passive rather than reactive, you'll probably want to grab a Mekanism to save your teammate in clutch moments. Arcane boots are a must-have to keep your mana pool up, and aura items like Ring of Basilius and Drum of Endurance benefit both your team and your Golem. Of course, you'll probably be the one buying courier, and the single most effective thing you can do as a support is to keep key areas warded at all times. During laning, this will probably be the rune spots as that's where most mids will gank from, but you may also want to block jungle spawns or place it in between the enemy's towers while pushing.

If you're swimming in gold (not likely) grab an Aghanim's Scepter+Refresher and laugh as your four Golems destroy the enemy team.