Gesso is your friend. Gesso is artist's primer. Gesso can rescue a bad painting and give you a new start. It is acid-free, so if you want your work to be around a thousand years from now then by all means use gesso. Gesso comes in a number of colors - you can get it in white, black, gray, yellow ochre and red ochre. Daniel Smith carries it in venetian red and yes, gold metallic gesso. I bought some of that by mistake, thinking it was golden ochre.
You'll notice I didn't use gesso above. I used a self-priming flat paint. It's an experiment. And the art world has a precedent for using house paints, although they are not as stable as paints designed for artists. So keep that in mind. One of my favorite ways to prime hardboard panels uses bonding house paint primers tinted to colors I love. There's something about working on a painting that has a color you LOVE as its base. All the while you're working you're seeing that color you love. And if you let it peek through here and there it gives the painting some cohesiveness.
This primer needs to dry for 4 hour before being recoated. So I'll come back to it later in the day to see if I need another coat of primer or if I think I can begin working on it as it is.
Check out the other 31 Days of Art posts.