Do yourself a favor by buying an angle-tipped brush as opposed to a flat-tipped one- they make staying in the lines a lot easier.
Note: We didn’t prime or paint the inside of the doors, but our approach would be to prime/paint them first and then wait five days and turn them over and prime/paint the outside (that way if anything got a bit imperfect after being flipped face down, it would be on the inside- an therefore less noticeable). After two coats of latex paint you now have to practice patience.
Of course by removing the hinges you’ll be removing all the doors, so finding a place that you can lay out a big fabric or plastic drop cloth (which are about $2 from Home Depot or Lowe’s) is a good idea.
Once you have your drop cloth in place, lay out all your cabinet doors and drawers so you can paint them all together in one convenient spot (and have full access to the frames of the cabinets in the kitchen). Then if you’re replacing your hardware with something that won’t fit the existing holes in your doors and drawers, you’ll want to pick up some wood filler (it’s around $6 a tube, which is all ya need) and fill those existing hardware holes in all of the doors and drawers.
Then it’s nice to wash everything down with a little soap and water to cut the grease and the spills that have built up on the doors and drawers over the years.
Nothin’ like a little sponge bath to get you in the mood to makeover your kitchen… Now it’s time to remove all of your hardware and your hinges (regardless of whether you’ll be reusing it or replacing it- and it helps to store everything in a big ziplock bag so you’re never short a screw).
If you don't have a window, it'll be even more vital for reflecting what light you do have.