Paint spotting

I can't think of much beyond what the others have suggested. 1. Possible that the paint could be old, or you're using a thinner not fully compatible with that paint. 2. Possible the thinning ratio is not ideal, some paints really do better when thinned a great deal. I've sometimes thinned Model Master Enamel as much as 1:1 for a 50% thinner mix.

I'd recommend maybe trying some scrap plastic sheet, or shiny printed cardboard box material, like store purchases are sold in. Experimenting on that with thinning ratios, pressures and distances can prevent mistakes on the model. Finally, maybe a fresh paint supply from the hobby shop will get this sorted. Best of luck with a fix. Please let us know how you make out.

Patrick  

Went over it with some 1000 and 2000 grit sandpaper and it mostly smoothed it out. Put more thinner in and gave it another spray. Had the compressor at about 15 psi, turned it down a little over 10 psi. Still not perfect, but I think once I get into weathering, etc. it may come out OK. Which is good since I've put a lot of time into aftermarket photoetched stuff on this one (Tamiya Sd. Kfz. 184 Elefant). Thanks for everyone's help.

Too much air pressure is another cause of such spots.

It was caused by the paint drying before hitting the surface.  The paint was not thinned enough or you sprayed too far away.  Keep in mind that the same paint you've used before doesn't remain the same in terms of viscosity.  

What you can do is to lightly sand the model with a paper towel or Mr. Clean Magic Eraser or something similar, and then spray again.

Texture, like raised dots on the paint. I read this morning on another site that a user was holding the airbrush too far from the object and the paint was drying before it hit the object. I wouldn't think this is the problem since I've been doing the same thing I always do and this has not happened before. I thoroughly clean the airbrush after each session.

What kind of spots?  Different color, but smooth, or spots of texture, like rough spots?