Ok, for the other points, many people on here have given you some excellent advice, follow it.
For the presentation, I am going to share a few things taht have been told to me, and the I have learned about public speaking:
1. Practice, practice and practice some more. practice until you could do the presentation in your sleep. I have acted in 2 plays and done a few largeish presentations in my short life, and I could still do them all today, at a push.
2. Smile. It puts the audience in a better mood, and you feel better when there is a sea of smiling faces looking back at you.
3. These next noes are about the writing if the presentation, because if you are confident that the presentation is the best that you can do, it will make you feel much better.
a. Intro-Body-Conclusion. Tell them what you are going to tell them, Tell them, and tell them that you've told them. This reassures the information in their mind, and helps you to get your oint across.
b. Use jokes, or funny pictures to keep them interested. I did a presentation about a safety guard for a potato harvester, and the first few minutes were me talking over an animation of a farmer getting sucked into a piece of farm equipment. It wasn't nessecary, but it engaged the audience, then all I had to do was to keep it.
c. Bullet points are your friend. Don't put paragraphs of information on a slide, put 3-4 points per slide, and a max of 2 sentences per point, but try for as little as possible. Remember that there are 2-3 different mode of information for the audience: you, the presentation slides, and an optional handout. They should all be different. The handout has all the iformation for them to read as and when they want to, you are telling them only enough to get your point across and keep them engaged, and the slides should be there simply to keep what you are saying in their heads.
d. Start with a long presentation, and shorten it over a few iterations. Just keep going back and clipping it until you are happy with it.
e. Have an ending. It's best to end on a joke, or a snippet of information that they will keep in their head, don't just get to the end of the slide and say "Umm, well that's about it ..."
And just remember, confidence comes from two things, practice and experience. You can't get the experience yet, so hust practice.