Particularly after transforming E. coli, students usually find this lab to be pretty straightforward.
Students still struggle with the unit analysis required to "compute the volume containing XXXX amount of DNA". I usually provide a basic example, along the lines of "if I have a solution that is 5 g/ml and I need 10 g total, how much solution do I need?" and then suggest they use the same reasoning. I also offer to double-check their answers if they'd like.
A common issue is "not enough PCR", especially if there have been a failed transformation or two. (There's usually plenty of plasmid.) If there's more than 100 ng of PCR DNA, I usually tell students to go ahead and try transforming anyway, with the warning that things may not be efficient and they might consider retrying their PCR while the incubation is going.
Wait three full days before trying to pick colonies. Yeast double every 2-3 hours on dropout media like this, so it will take time before colonies are visible. They're usually visible (but small) after 2 days -- too small to do anything with.
When interpreting their results, I usually ask students to think about why we plated on both the leucine and uracil dropout plates. What does it mean when cells are growing on one or the other? (FYI: the leucine plate is the transformation control -- it tells us whether we were successful at getting the DNA into the cells. The colonies on the uracil plate, though, necessitated both successful transformation and successful genome editing -- they're the colonies we want to move forwards with.)