1) Read. If you know the morning report topic ahead of time, read up specifically about it. If not, read in general. Your program may assign weekly readings, but if they don't, then get the main text for your specialty (such as Harrison's for IM), and read it on your own.
2) If you get asked a question that you don't know the answer to, try to reason it out if you can. Think out loud so your attending can see your thought process. And after your morning report, go read about that topic so you'll know for next time.
3) If you're doing a presentation, prepare enough for it so you know your material cold. Particularly when dealing with off-service faculty who may ride you a bit, making a good early impression is essential so they get the idea that you're a guy or gal who knows their stuff. Some showmanship can help too when dealing with aggressive personalities. I got an off-service team off my back once by doing a brief "chalk talk" about opiates, where I drew the structure of morphine and some of its derivatives from memory while discussing their different properties. The attending and senior residents had no idea that I had deliberately memorized all those structures right before giving the talk. But the important point is, they left me the heck alone after that when it came to the aggressive pimping.
