Eldrich Blast. Singly the best Warlock spell. You will keep him at range. At sencd level, give him Hex spell and the Charisma and knonk buffs for the eldrich blast. When combat opens, use Hex spell to make sure the the target takes extra damage Wyll hits it, an Eldrich Blast the fire out of it. At 4th level, increase his dex and Con for extra modifiers to hit, more hp, and better concentration to keep Hex on target. He's among the easiest of the companions to use. Hope that helps.......;-)