Are you using a compressor/spraygun or an aerosol?
It will also have alot to do with fan pattern and the ammount of paint the gun is throwing out.
If using a spraygun, what size tip and pressure are you running it at.
It took me along while to master spraying and now do cars for shows in candy etc, so you will improve. However, each spraygun is different and will take time to get used to.
Generally you would lay a dust coat down first which is to act as a key for the next coat and should wait until it goes tacky before you put your next coat on. I use a 50% overlap with my spraygun but some people say 75%, but you will find the best way of spraying yourself.
Go on youtube and type in spraypainting, loads of good stuff on there.