Go and read through http://latex-beamer.sourceforge.net/ and especially its manual that comes with the tarball on https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fsourceforge.net%2Fproject%2Fshowfiles.php%3Fgrou p_id=92412&package_id=97753 .

You will absorb a different way of approaching a presentation, even if you won't use that LaTeX package to create slides.
But typing some by hand might make you a skilled craftsman of that trade...

And for the speaking part, join http://www.toastmasters.org/ !