Refillable pot + Early Dark Seal on Enchanters
As in, after Frostfang get it on your next back. It's only 350 gold, but can give quite a bit of AP, which most enchanters love since their shields/heals scale off of it. Increased healing from potions due to Dark Seal and the mastery, combined with all the increased healing masteries and Forbidden Idol items, means that the Refillable Pot sustain scales well even into the midgame. For some champs, it might even be worth to upgrade to Corrupting Pot so you can contribute more damage in fights and heal yourself quite a bit. If you die and lose Dark Seal stacks, it doesn't even really matter since you only spent 350 gold on it in the first place.
What do you guys think of it? I'm pretty new to support, but this strategy has been serving me well in my Lulu games.