Lectures are boring, but he explains concepts really well, so I force myself to go to all of them, even though it's an 8 AM class. Discussion sections are pretty helpful; the TAs will review homework problems (which are graded and basically free points) and additional practice problems.

To study, go over his lecture slides (it includes material not in the book), review example problems in the textbook, and do all assigned problems. Don't focus too much on his derivations - he hasn't tested on that so far. Just study the formulas and how to apply them.

All his tests are multiple choice, which may or may not be a good thing. His first midterm was cake - the majority of the class got an A, average was 27/30. However, his second midterm was considerably more difficult. He added ten more questions under the same amount of time, plus some of the questions were VERY time consuming. The average for the second midterm was about 26/40. I still did well on the second midterm by learning how to do homework problems really quickly. Also, he lets you bring cheat sheets to every test, so don't waste time memorizing formulas. But note that you can't rely heavily on your cheat sheet if you want to finish the test on time, so try to make your cheat sheet as concise and easily accesible as possible. Overall, good professor for Econ 41.

Professor Hahn is an excellent lecturer. He's very good at explaining the material and his exams are very fair (plus you can bring cheat sheets, so that makes them easier). He posts the lecture notes online and gives you a list of practice problems at the beginning of the quarter, which is really nice. If he teaches this again, you should take him.