Practice makes perfect and all that jazz. I don'r know what you know and what you don't know so I will speak as if you know very little or nothing at all.

Painting is all with the wrist. The is a right way to swing a gun/can and a wrong way to swing.

The wrong way is to grab your gun or can and lock your wrist into a hard position. Then you fan the gun like it is on a string and you get uneven coats of paint because as you swing the gun away from your front and over to the side you wind up with heavy paint in front of your body where the gun is closest to your work. As you fan from side to side the paint will have lighter coats of paint because the gun alternates from being close to your work to being far from your work.

The correct way to swing a gun is to unlock your wrist and let it flex as you move from side to side with your body. You always need to think in terms of keeping your gun parallel to your work as you move from side to side. If you are holding your gun six inches away from work, flex your wrist as you move from one side of your work to the other, keeping that six inch (or 8 inch or whatever) distance all the way from end to end.

Fanning your gun is the easiest mistake to make. Flex your wrist and work for parallel action.

May be you already know this. Maybe you don't.

Pretend you are working for the man where you have to be fast and you have to be good. Paint is expensive so you do not want to use too much and the boss will only tolerate occasional touch ups.

Some of you talk about working on the horizontal. I understand that. But if you can find some cheap paint to waste, try painting a scrap vertical surface so you can get the feel of how much paint to lay down before you starting having problems with runs, sags, and curtains. Go for the gusto and try to make it run or sag. It will be the best teacher that you will ever have. There is no feeling of "aw, shit" like when you make that last pass and all you can do is stand there as your paint starts moving for the floor.

Are you shooting acrylic lacquer? Or are you talking about the old nitrocellulose lacquer? If you are talking nitrocellulose lacquer, where are you finding it?

I prefer to shoot on the vertical surface. You can do single sides as you speak of but I would suggest you roll the cabinet back over and pull your stencil when it is on a vertical plane so you don't drop peeled stencil material into your fresh paint.

As mentioned, practice makes perfect. I learned to paint by painting model cars. I learned to paint by applying way too much paint and watching it turn into runs that ruined my paint job.

I learned to paint by doing a small amount of reading on the proper way to lay down a coat of paint. I learned by making a few mistakes.

The Walmarts in my town carry some cheap rattle can paint for something like 95 cents per can. Go buy some cheap paint, some some plywood, a piece of sheet metal, an old car door, and old refrigerator door, and have at it. It will cost you a few bucks but everything we do has the price of tuition involved.

Google up " proper spray can painting". Or painting tips and techniques.

Get some cans of cheap spray paint and push it to the limits.