Quote from Kholdstare
You're overequipped. The Enderdragon is a pushover. Drop your gear to iron instead of diamond (so that in the event that you DO die, you will only be losing iron gear instead of diamond), grab a ton of snowballs and arrows (or an Infinity bow if you so choose) and a pumpkin and you're set.
If you absolutely need enchantments, you're going to want Infinity and Power. You don't really need much else. Feather Falling, however, is pretty great and if you want to climb the towers instead of sniping the crystals, grab it for sure.
I agree. You can beat the dragon with no enchants on iron armor. If you don't have infinity 1 stack of arrows will suffice. Just use snowballs to knock out regen crystals. It's a long drawn out fight so don't get nervous or anxious. She tends to fly around out of distance a lot