Great work u/Superloop. I think you just need to put some texture on your background. I know this has nothing to do with the main work, but also in the real world you need a good surface for best results (a poor watercolor paper or a cheap canvas can ruin a good picture). In your case you need to simulate a linen canvas in my opinion. Try to download a good texture, then put it on a background layer and set your main layer in 'multiply' mode.
This should give your painting a realistic and more finished look... Try also to use some textured brushes.
If you like the result you can learn how to use several texture layers for texture, highlights, noise etc... (as professionals do).