Quoted from Langless28:
Joining this disaster club. Luckily it was only the top of a head being painted black with decals (no fear). I did light coats of 2x gloss black to build 2-4 min apart. Waited two days, sanded with 220 and did the same painting method. Waited two days to use rusoluem clear enamel and this happened. I know I did it too thick. Sanded all the way back down until all wrinkles were out. Redid a black layer. Super light clear coat 2 days after a very minor hints of wrinkling. Stopped and now I will sand flat and wait a few more days with it out in the heat. Then try to do another round of clear. Funny if you can notice the whole head is taped off. All other sides (including original black paint and silkscreen) faired just fine and are perfect. Of course the two perfect sides will be covered by decals ahh.
So yes I think lighter coats is 100% the key.
Its a bummer of a club to join but in the end you'll learn how to dial in spray painting from these mistakes