First and foremost..... PREP
I say this in each and every tutorial, prep is the most important step for a long lasting beautiful finish. Even if your paint can says "no prep", you'll regret skipping this step in a year or less.
Clean your piece well with a degreasing cleaner. I use Sugar Soap (in my Etsy shop), it's an eco friendly cleaner that works just as good as TSP.
Make any necessary repairs...sand out deep scratches, fill any cracks and sand smooth, ect...
Then take 220 grit sandpaper and do a quick scuff sand everywhere that you're painting. This is a crucial step that will key the surface and give the paint something to really grip onto. You don't have to get down to bare wood and you also don't have to get rid of all the glossiness if using a high quality chalk paint (latex paint users-use a deglosser found in most hardware stores). This is simply a quick scuff sand.
Then wipe down with plain water and remove all dust/residue
For a jewelry cabinet this size, prep took me 25 minutes which included repairing the corners. Definitely worth a finish that will last forever!
This piece is dark wood and typically would need a primer first to eliminate bleed through. Frenchic Furniture Paint has the primer built in, so I don't need to do this step. But, if you're using another paint brand and you're piece is natural wood, has visible knots, or is a dark wood, prime now