Sit back, take a break.

Seriously though, having all the power in the Uni/Multiverse has to be really hard work. I mean, keeping track of everything at once must be taxing… speaking of taxes, I would throw a gigantic party over the fact that I would no longer need tax since I control everything. We wouldn't need to buy or sell from other countries/planets so we could just revert to the old days of 1866 where you trade something equally vital to what your selling. No more wasting copper and nickel on making useless circles for trading.

Heck, I'd just throw one massive party for everyone, even the slaves, and give up my power. Let them fight over masses of atoms, I'd retire.

Hmh… First I'd take a nap.

Then I'd comb through the masses, looking for signs of a resistance.

:D There's always someone tryin' ta ruin my naps. <3

Well, the Doom Fortress of Darkness comes first of course. Presuming that I somehow figured out how to do it I'd have myself turned into a seven-foot tall freaky cyborg. Then of course build up my legions of doom and exploit the masses, (hey, I'm an evil supervillain in this scenario– I'm required to do this by law!)
I'd let rag-tag pockets of resistance pop up too, just because it makes things more interesting. At least until I get tired of that, then I'll annihilate 'em.

Someone
Suppose you, a ruthless and evil dictator, finally conquers everything…?

Then your name would be Barack Obama.

Concentrate all the world production on ice cream. After that, who cares…

A)

kill all three of my most trusted advisers. I would then tell their children I only did it because they were ugly, then ship their children to the 3 corners of the universe (because it has 3) in hopes of them growing up wanting vengeance and creating their own rebellions.

I do not want a boring life.

B)

hand my control over to my most selfish and evil servant, in hopes she/he will cause true chaos among the worlds. I will then create the rebellion myself. Scruffy looking Studs/chicks, dig rebellions.