Ok , once primered (with plastic primer

) leave to dry . then use 800 or even higher for better results (wet) to smooth primer , then spray , if you have already sprayed and its gone wrong , just allow to dry for a day at least then wet 800 again till smooth and paint again (you already have the primer on so go straight to painting)...
You have done most of the work now if you have primered and masked up , so its just a case of getting a nice finish , what i would say is to spray a couple of light base coats on and allow to dry then apply 2 nice even coats allowing to dry in between , hope this helps.
I have just sprayed an eyebrow spoiler and went wrong lol , but smoothing it down and repainting and bingo! a good finish was achieved...practise makes perfect
oh and i know what you mean , I spray in my living room and end up with red paint up my nose
