Hi all,
Try applying a coat of Future Floor Wax and immediately (while the Future is still wet) brush on your paint. I find that this is giving me a nice, even and smooth color.
I had tried mixing the paint and future, but had issues with bubbles and such. This way is working much better.
Good Luck!
Edit: Oh, I'm using Model Master Acryl Paint (Acrylic). I have not tried this with other brands/types of paints. Be advised.
Thanks!