You will have a lot of opportunities to present your research during graduate studies. Make good use of them to learn how to present well. This is an acquired skill. A very few people will present well first time they try it, but in time you can really master this skill and deliver a sparkling presentation when it really matters (e.g. a job talk, a conference presentation, your qualifying exam, etc.) Here are a few tips that should help you along:

• When making slides, count on having roughly one slide per minute of your talk. If you tend to speak slowly, make even less slides. There is nothing worse than when a speaker crams too many details into the presentation and goes over time.
• Use large enough font. A golden rule using a default PPT font or one size smaller. Don't go over 10 lines per slide.
• Use large enough pictures. Small graphs with thin lines will deliver no message, as they will simply be invisible to the audience.
• Use colors that are visible during the presentation. Sometimes things look different on the computer screen than on the projector. The best way to find this out is to do a practice talk with the projector.
• Don't put complete sentences on slides. Instead, put clear hints to the points you want to make during the talk.
• Think about what message you want to deliver. What is it that you want your audience to carry with them, after the talk? Deliver this message in the second slide (the title slide being the first), enforce it with your talk and repeat in the conclusion. Put only as much information as needed to deliver the message.
• Prepare your slides at least a week before the talk. Working until morning hours the night before the talk or on the plane flying out to the conference will result in a very sloppy talk.
• Do dry runs of your talk at least three times before actually presenting. If possible, try to have some audience (your advisor, research group, friends) during those dry runs, and pretend that you are actually delivering the talk in the target venue. Ask your audience after the talk for their comments and suggestions. If you cannot find any audience practice alone.
• Having stage fright and really hate speaking in front of many people? Practice should help you overcome that. Everyone dreads speaking up in public to some extent. But doing this often, helps you get rid of your shyness and actually start liking the experience. Besides, if you follow the previous suggestion and practice your talk, you will be able to deliver it well even if you get very nervous, because you practiced so much that you know it by heart. Also keep in mind that audience is usually sympathetic and will rarely give you hard time and ask nasty questions. They come to learn.
• Don't get discouraged if you deliver a bad talk. Just practice some more and do better next time.
• Use any chance to speak. Be a teaching assistant, do class presentations, speak in seminars or research group meetings.
• When actually delivering the talk in the venue, be enthusiastic and energetic (if you don't feel like this about your talk, why should your audience?). Speak slowly and look at your audience. Think about what you want to say before saying it. Be aware of your behavior and of the audience's attention. Don't wave hands, mutter, or walk up and down. Bring a laser pointer (speakers that point with their hands on the projection panel are abominable) and point only when necessary (drawing circles with it while talking will distract the audience).
• There are numerous books about the art of speaking well. Buy one or enroll in a public speaking class.

Short point summary

• Make visually good slides
• Don't put a lot of details on the slides
• Decide on a message you want to deliver, then make sure you deliver it
• Practice, practice, practice
• Be aware of your behavior and surroundings during your talk
• Buy a book on presentation skills or enroll in a public speaking class