Most students have to (or get to?) do several presentations throughout their graduate career, including talks for classes, thesis and dissertation, professional conferences, and the general public. Unfortunately, students don't often get a lot of training or feedback on how to deliver these presentations effectively and trial-and-error is the only way to learn how to improve.
"Public Speaking for Psychologists" offers general tips for preparing for and delivering talks as well as specific guidelines for how to deliver research talks, poster presentations, job talks, and presentations for lay audiences. Here are the 5 things they suggest keeping in mind when getting ready for a presentation:
Reference: Feldman, D. B. & Silvia, P. J. (2010). Public speaking for psychologists: A lighthearted guide to research presentations, job talks, and other opportunities to embarrass yourself. Washington, DC: American Psychological Association.