The thing with nerves: in itself, they are not really a problem. It turns into a problem when it impacts your talk.

A couple of ideas to deal with this:

• It is really useful to watch recordings of yourself, to find out that breaks you take never are as long as you feel they are. Controlling my breath is my number one problem, especially at the beginning of presentations. Don't be afraid to take a couple of seconds at the beginning of your talk to breathe normally.
• Related to this: knowing some breathing exercises can be a huge help. I regularly use the simple “count your breaths”-technique to shift my mind off things as I’m counting down to the moment to start my presentation.
• Another idea is to add something in your presentation that allows you to settle: a short video or a question to the audience. Anything that allows you to be quiet for a couple of seconds can be a huge help.
• Rushing to the stage (traffic, not knowing which stage you’re on, etc.) makes me more nervous. The more elements of uncertainty you can remove up front, the better. One less thing to worry about.
• Practice, practice, practice. Not just in front of a mirror, but actually practice in front of somebody. That's a frightening experience, but just like you need to get comfortable with your message, you need to get comfortable with the pressure too.
• Connect with your audience. It always helps me to be a little early and have a chat with some people that are walking around. Focus on them, try to learn something new. Have fun. Even better if you can actually loop back to this conversation in your presentation.