How can you kill Caesar?

Pro-Legion way:

I just sneak killed every single guard along the whole camp and stole there weapons and then went into the tent with my followers and disarmed one guard and got his fist and owned them all

That's one way. Then of course there's the hard (fun) way. You start by walking into his tent....then shooting him. (Or chopping, punching, lasing, exploding...whatever you like).

Be prepared to fight your way back out of the camp though. His immediate guard force will be armed with displacer gloves, and in close quarters will drain your health very quickly. So have plenty of stims or means of healing. Once the tent is cleared, the outside guards will be much easier. Either way, I wouldn't recommend taking this on until....at least level 15. Though 20 would probably be better. Enjoy!

(Obviously this will vilify you with the Legion)

Displacer gloves? Ha, I wish! Only Caesar has one; the rest all have ballistic fists, which do 2x the damage.

The easiest way I've found is to use a high-powered gun (which has a short reload time) along with some armor-piercing bullets. This Machine + AP .308 rounds = massive death. If you bring along a companion with one of their optimum weapons, like Veronica equipped with Pushy or a ballistic fist in power armor, killing Caesar becomes a cakewalk.

Personally, I bring along Boone for RP reasons, but you have to keep an eye on him since he requires you to storm the Fort instead of walking right up to Caesar and fighting your way out. He's especially difficult in close quarters, like in Caesar's tent, since he needs to be at medium range to be effective. Giving him a melee weapon that ignores DR, like a chainsaw, and then changing his combat settings from ranged to melee seems to alleviate this problem.

Also: stimpaks. Jet too, if you rely on V.A.T.S. and find yourself in a tight spot.

I killed him with my AMR (Incendiary Rounds). Of course with Slasher, Psycho, Med-X, Turbo(Lots of Turbo), and my Ranger Sequoia for his guards

Boone and I rocked that place.