Be critical of yourself but never be too harsh on yourself, give yourself time to learn and time to get inspired by anything around you. Don’t forget that you can make nearly anything to become a theme If you want you can even have a notebook with you, where you can write your ideas as fast as they come up. This will help you make a photo session schedule. If you are frequenting a photo course, then don’t forget to show every photos you have taken ( or nearly ever one of them if they are over a 1000 so that your teacher can help you with further motivation and future inspiration.
Remember there are so many ways of taking photos, from fashion to nature photography From street photography to culinary photography. Sooner or later you will find your own most popular themes and learn from all the critiques you get from those who know more than you do.