In the interest of becoming your own best teacher, put several of your paintings on a wall and stand back. Identify one aspect of your work that you'd like to strengthen and one that you know you can depend on. For example:
"I have trouble reading values correctly when all the colors are present. I think I'm confusing intensity and lightness"
"I am becoming much faster at mixing a color that works for whatever comes next"
If you keep the question of how to strengthen your selected issue foremost in your mind for the next month, or so, you will definitely see real progress. Devise a plan, such as what kind of preliminary studies you will make, or which questions you will keep in mind as you choose values and colors. Write your plan down, and post it somewhere you'll see it when you get ready to paint. If your plan involves relying on what you feel confident of, so much the better.
Find a new scene or photo that appeals to you, and make studies and perhaps an attempt at a proper painting, keeping your issue of the month on the front burner.
In class, we'll share our selections and offer one another suggestions about how to move forward.