This is a question that is very difficult to answer because only you can know. Most of us at some point have overdone a painting or drawing and regretted it. Drawing and painting something isn’t a job that has an identifiable beginning and end. For some the completion of a painting could take many years, for others just a few hours.
Sometimes being given a topic is easier than having complete freedom to draw or paint what we like. If you have no guidelines then I would suggest drawing and painting what interests you. Sometimes we aren’t sure what interests us, so then it is best to take some time to observe life, nature, the weather, everyday life etc. and see what inspires us. I always find that going out helps with this, it is hard to be inspired when you are sat at home or in a classroom with the same four walls!