Somewhat obvious, but try to anticipate what questions might be asked, and come up with good responses in advance. In addition, you can potentially create backup slides to support key points.
Make sure you understand the question(s). Feel free to ask the questioner to clarify. It's also fine to try and paraphrase their question and ask if you understand them correctly. In fact I recommend doing this even when you're pretty sure you understand, since it (i) buys you time to think of a response (ii) helps others in the audience who might not have heard (iii) is especially useful if the presentation is recorded and the questioners don't have a mic.
Try to keep your responses brief and to the point. This gives time to more people to ask questions. Rambling on and on when a short answer would suffice often makes people think you don't know what you are taking about. In a technical presentation it's often much better to simply say "that's not something we've considered, interesting", or "that's something I'd need to think a bit more about" than to try and bluff. But obviously you don't want to do this for every question.
If someone is being really awkward and/or you really can't seem to answer this question, better to suggest taking it offline to avoid hogging the whole q & a period.
Try not to get too defensive.
When practicing your presentation, ask people to be as picky as possible and make you think on your feet. Hopefully the actual questions you get will be easier.
IMO handling the q & a well is almost as important than the presentation itself. It's a real shame when I see some interesting work with a good presentation and the reviewer then undoes it all by not being able to respond well to basic questions.