u should lay down about 3 coats of paint to ensure an even color, but if u notice that u screwed up let the paint dry 24 hours and sand it down, u can paint over the dry paint with the same or compatible paint if u wait for it to cure the 24 hours, but the 3 coats should be laid down with about 15 minutes between each coat to allow the solvents to flash, basically it should be slightly tacky but not wet. when u do get to the clearcoat stage u want to wetsand with 1000 gritt, the clearcoat doesn adhere right if u use higher than 1500 gritt. Wetsanding will take away the shine, but it will come back with the clearcoat or even a good polish if u do it right. u can pretty much eliminate the orange peel with a bit of effort by doing about 6 full wetcoats of paint so u have extra film build to sand down, then u can sand with 600 or 800 grit depending how bad the orange peel is and work your way up using as many grits as possible (if u can find 3000 gritt that would be the last grit but i used 2000 since thats the highest i could find) make sure u spend enough time with the finer grits to remove the scratches from the coarser grit.
Before

Wetsand 800/1000/2000, didnt come out that great since i didnt have any 1500 and i didnt spend enough time with the finer grit, in person u can see the small scratches (i'm going to resand now that i have finer paper though to get rid of the scratches)

After wetsand and Polish. the paint still has a slight orange peel to it but is about 70% reduced, i was informed that this could be because of "ghosting" which brings back what the origional spray pattern was like, the "ghosting" occured because of the heat from the rotary polisher. with orange peel the paint cures at slightly different times due to the high and low spots and with the heat from the polisher it caused the solvents to shrink or something which brought back the slight orange peel effect. I'm going to hand polish the next attemp to see if it still happens. It should be fine with clearcoat though as u dont need to polish it the same. still turned out da#m good though.

smaller projects will be easier to perfect as u can concentrate more time into it. The orange peel was pretty bad on this door due to gun and compressor problems...so i tried to fix it without repainting. hope it helps some. oh yea...i have about 6-7 full wetcoats on this door, took off a fair bit with the process and i have to remove some more.