Take off all cabinet hardware including hinges. Label and place in bags.
Create a map of the doors and label them in the corner under where the hinges will go, use painter's tape or label on your drop cloth.
Set-up paint station for drawers and doors.
Tape drawers so that you are only painting the wood part, but not the whole drawer.
Lightly scuff already painted cabinets with extra fine sandpaper or green Brite pad. Pay extra attention to brush marks and imperfections. Now is the time to fix those.
Wipe down cabinets and all surfaces to be painted with a deglosser.
Make sure cabinets are completely clean and dust-free.
Trim out areas on cabinets with a brush that the small foam roller will not be able to get. You want to work in stages.
Once you have trimmed a few areas or ridges in the doors, use a small foam roller to paint all flat areas with high-quality paint like Sherwin Williams Emerald Urethane Trim Enamel. Working in thin layers will be your best bet.
Let the first coat dry and repeat the painting process for at least 2 coats of paint.
Look at your cabinet from multiple angles to make sure you are painting all areas evenly.
Let the paint cure for as long as you can (at least a few days).
Put hinges back on and put doors and drawers back in.