How to paint correctly?

Hmm, I'm puzzled .On the picture it doesn't really look bad, on the contrary,your black outlines are fab👏

So let's keep exploring, what is the stage of design at th moment? Has it already been heat fixed?

How is your paint when you're applying it? Is it smooth, or somewhat getting thicker, than when straight from the jar?

How many layers of red paint are there? Have you waited until each one of them dried completely before applying the next one?

Painted design usually repeats the texture of fabric itself, and just makes it a tad stiffer. Is it possible that the are some small lumps of cotton on your denim itself? Like those that I marked in yellow...

Hi Angely, I'm sure someone will be up to help answer your question soon, but let's develop it a little bit first to try and understand the issue better.

It would make it significantly easier to see what's the problem, if you attached the picture of "clumpy" places?

I didn't quite get, does it happen already on your fabric or paint changes its texture, say, on the palette?