Manage your time
Identify your best time of day (you may be a morning person or an evening person) and do the important tasks that need the most energy and concentration at that time.
Make a list of things you have to do. Arrange them in order of importance, and try to do the most urgent ones first.
Try to vary your tasks in a day. Vary dull jobs with interesting ones, tiring jobs with easier ones.
Try not to do too many things at once. You could try to start something else if you have to wait for the next stage in a previous task, but if you have too many things going on at the same time, you will start to make mistakes.