Here are some links to guides for giving scientific presentations. If there's something else I should add, please let me know.
My source for this group of pages was the home page for Physics 596 at the Ohio State University. This is a course taught by John Wilkins; the title of the course is Writing and speaking about physics and astronomy. Wilkins has lots of great advice about writing papers and giving presentations.
Page maintained by Dave Feldman. Corrections or comments should be sent to firstname.lastname@example.org.