This is a crucial session in any presentation. If you handle questions badly you, risk undoing all the good that you have done. Remember:

Share the question (where appropriate) with the rest of the audience who won't have heard it because they were all too busy thinking about the questions they wanted to ask. Think about how you are going to answer the question. Only answer the question - don't get side-tracked and don't go into too much detail. Politely check that your answer was okay.

If you don't know the answer to a question, don't worry. In this situation you can either offer a partial answer to the audience and hope this will create a discussion, or you can admit that you don't know - but offer to follow it up and find out if appropriate.