Question: I have beaten every boss but the moon lord with out potions, but I am wondering if it is even possible to do it. I would like to hear strategies on how to do it.

Answer: 
there are a few methods, most being quite cheap. There was this person who set up an essentially AFK playthrough of terraria and for the Moon lord the character was teleported around at seemingly specific timings. You may also be able to set up a hoik track to dodge his attacks. There is also, of course, practicing dodging his attacks and having a good arena to fight him in. for the arena have honey in bubbles(from party girl), heart lanterns, campfire, heart and star statues set up on one second timers, a couple of layers to block his laser, have the nurse and dryad move in just below the arena (for instant healing and extra defense) and anything else you would like to have. To make navigation around the arena easier, I recommend using the UFO or if you are doing an expert playthrough, use the shrimpy truffle. Hope this helps!
With this method I have killed him several times on expert mode with no potions including buffs.

**Arena**

What I did is set up an asphalt sky bridge (with campfires and heart lanterns) across my medium sized world, which honestly is more than enough space. 10 tiles above the skybridge I placed another dirt bridge (though any tile will due) This is to block attacks such as the laser from the eye in the head. In the top dirt bridge I also cut out bits every so far so that I could get a yo-yo (Eye of Cthulhu) up there to attack the eye.

**Weapons**

Other than the yo-yo I also used a Stardust Dragon staff for damage. For the hands you have more options as they are more easily targetable. Things I've used include the yo-yo, Phantasm and Daybreak. Depending on playstyle you could really use any end-game weapon you like or have. I tend to stick with other melee items as I use yo-yos as my main damage source since you will have to attack through the bridges meaning that I will use melee damage supporting armor

Once the heart or core is exposed I use Solar Eruption to attack along with the Stardust Dragon. As the core will be underneath the skybridge you will need something to pierce through tiles to hit it. You could setup some platforms to get a yo-yo through the floor if that is what you would prefer to use.

**Armor/Accessories**

Health is easily sustained by wearing a Charm of Myths and Celestial Shell along with the Valhalla chest piece. Considering you also setup campfires and heart lanterns you should regen any lost health fairly quickly. You will still need to dodge however and if you are too low you can simply out run the boss until you feel safer. He will teleport to you but as long as you jump over the hands, none of the projectiles should hit you will moving at top speed.

Other accessories I used are an Ankh shield, Frostspark boots, Yo-yo bag, and a Destroyer emblem all with warding modifiers. Mounts and wings are not necessary as you will you will have the second bridge right above you. And the asphalt means you will already be moving at high speeds, mounts wont make much difference.

The Valhalla chest piece is the only required piece of armor for the health regen. The boots and headpiece are up to you. I used the Shinobi Infiltrator for the increases to melee and summon damage.

**Strategy**

During the first phase you can focus on either the hands or head first. If you are attacking the head then you will want to be in between the hands and attacking with the yo-yo. When attacking the hands you will want to be ahead of him running either to the right and attacking the right hand, or the left side for the left hand. I've seen people recommend to get both hands low and kill them at the same time after the head is down as to avoid the True eyes of Cthulhu until the second phase. I find their attacks easy to dodge and get them first, so that the stardust dragon will focus the head.

During the second phase you will again be in between the hands attacking downwards with the Solar Eruption, yo-yo or other tile piercing attack. This will be much quicker than the first phase as your Stardust Dragon will only have one target and it does not close like the hands and head in the first phase.