Mandibular 1st molar is usually 5 cusps (while the others are usually 4 cusps; except Max 1st, where it can have cusp of Carabelli on L side of ML cusp)
Maxillary molars (esp 1st and 2nd): have oblique ridge that runs from ML to DB (mandibular molars not have oblique ridges)
Max 1st: Buccal roots are plier-handle shape; 2nd Buccal roots are in the same direction/contour
Also Max 1st the palatal root is usually extend beyond crown outline. There is also are cronal depression on palatal. Max 2nd the palatal root usually is within the crown outline.
You are lucky, you only need to get tested in sections, for us, we had only one test with all permenant teeth, deciduous molars, as well as root and crown x-sections.
Best Dental Anatomy book that I've found and use is the one by Woelfel.
DAMN IT! HuyetKlem beat me to it!