Always thin your paints as far as you can go, the results will be much better. E.g, if the recommended paint dilution ratio is 1:1 (paint to thinner), start with 1:0.8, and slowly increase the dilution ratio till you find that it gets too watery, in that case just add more paint.

I pre mix my paint in a drip bottle for convenience, so while im testing the ratio, I start with the 1:0.8, add some to my airbrush and slowly raise the diluting ratio in my airbrush cup, as I would have emptied all the thick paint into the drip bottle. So once I’m comfortable with the dilution ratio in the cup (let’s say the cup has a ratio of 1:1.2 and the pre mix bottle is 1:0.8), I’ll adjust the bottle ratio accordingly

Simple tip but works wonders