Okay, I'll start off with a couple or three of my favorites.
When I open a new gallon of paint, I take a drywall screw and punch a hole about every inch around the trough where the lid fits. This helps allow paint that gets in the trough to flow back into the can. (I learned this one the hard way one time when I put the lid on and smacked it with a hammer........ SPLUT! )
When I DO put the lid on and smack it with a hammer, I use a rubber mallet, or a dead blow hammer, and cover it with a rag to keep the stuff from flying directly into my eyes every time. It should be seated, but doesn't require a beating.
I use those cheap paper paint filters, but get the coarse ones. When done, I toss them onto the ground and fill them with dirt. In a few days, they dispose in one piece.
I like using Japan drier.
I like those cheap plastic pour spouts you clip onto the lip. When finished, I just let them sit out in the sun, and the paint gets so hard it breaks right off. I have about a dozen of them, so there's always a clean one, or one that will clean up quickly.
Nothing works like a paint can church key. And, they have a handy beer opener on the other end so you don't cut up your hand on those (NOT SO) easy open beer bottle twist tops. (Don't know about you, but the same beer tastes different in a can or in a bottle.)
Well, that's some of mine.
Any favorites of yours?
Steve