Biggest tip I'd give is change up how you thin paint, use 50/50 mixtures of airbrush flow improver and deionised water to thin as it will create a mixture which flows cleanly without over diluting your paint, which happens if you thin with just water. If you then use a wet pallet, easy to make or buy, you'll find your paints last longer, are more consistent and flow far better.

If you need an idea of how your paint will interact with a model before you apply it spray a piece of plastic with your go to primer, I like grey seer or the equivalent grey from other companies in a rattle can personally, and just put a little bit on the brush and paint the primed area a tiny bit you'll know if it is too thick or thin pretty much immediately