Chlorophyte Helmet, Valhalla Chestplate and Greaves, Fishron Wings, Master Ninja Gear, Ice Tortoise Shell, Flame Gauntlet and Warrior’s Emblem.
For weapons, use the Solar Eruption
And prepare lots of potions
Not everybody likes OOA though, and Solar Eruption is not for those who want to keep some distance.
What I did was I had some beetle armour, fishron wings, master ninja gear, some damage increasing accessories, as well as a few potions, mainly ironskin and well fed, as well as a phantasm + ichor arrows and rod of discord. Rod of discord is optional though, but it helps with the giant beam that comes out of the top eye.
Fight on a large asphalt bridge and try to keep the Moon Lord half-seen on the edge of the screen. Go too far and he teleports.
If that's not good enough, you could use any gear setup you want, make a looping minecart track, make a house for the nurse near it, place a honey bubble on the track, turn on autopause and you can heal when you want. However, it might break in the Journeys End update, as autopause does not work with talking to an NPC. However, this method is a bit cheaty.
Go ahead with the playstyle that suits you most.
Edit: Dang it I'm the last post. Two last second posts today :|