How much operative and wax-ups have you done so far? After a year of those courses you pretty much have this stuff in your head. If you're still in first year then you need to approach it differently.
It should be obvious what is a molar vs what is an incisor, stuff like that. That should be the first step. After that you should just come up with some things about each tooth that differentiates it from the others. For example the 1st max molars have the cusp of carabelli on the ML. This could differentiate it from the 2nd molar. The 1st mand molar has 5 cusps. The 1st max PM has the mesial groove. There's something unique about every tooth which should allow you to identify it. Just narrow it down.
Also if it's a real tooth you are looking at, remember that not everyone has the same anatomy and that some structures may have altered appearances or could even be absent.
