Have someone you trust and who knows the topic well ask you questions from a variety of standpoints. Practice answering asshole, condescending questions meant t

Have someone you trust and who knows the topic well ask you questions from a variety of standpoints. Practice answering asshole, condescending questions meant to trip you up. Practice off-the-wall/off-topic questions, just plain hard technical questions, etc etc. I did this with my research professor before my first talk and it really paid off -- I got a really condescending question and managed to deflect it and get some laughs too. Basically, just practice :)