So, the fun for me is always figuring out how to achieve a realistic painting that I like. Two things work for me.
1. "Pushing the colour". If I see a colour, I choose to paint more of it. Any hint of a colour, I find it and paint it.
2. "Lost edges". Example on this painting. Look at the painting and tell me where your eyes rest. For me, it is the space at the bottom of the left apple where you can't really tell where the apple ends and the background begins. That's a lost edge. Lost edges do that; they draw you in.