If you have learned a topic by yourself, then doing problems on it will give you best result if you do it just after studying. Now the progression of problem practice shouldn't be the problems of exercise first. At first, you should do the derivations of the formulae (if any from the book) after that do the examples done in the book. The best way to do examples, is that you don't see the solutions. First try to solve yourself and then check the procedure. This will boost your confidence. After doing the examples, jump into the exercise and start solving. Also, do revise the chapters in every 3 days, which will help you to sustain the procedures involved in solving the problems.

I hope my answer provides you some insight. Wish you a great eve!