Last week I was involved in a CPD session at our staff festival, aimed at people interested in presenting at events and writing for publication. My colleague Julie Allinson did the publications part - she recommended Mike Ashby's guide to writing a paper (PDF). I did the presentations bit, and it was based on a mixture of a recent LibMarketing slideshow on making good PowerPoints, and advice about public speaking that I'd previously written or read. It's worth a look particularly if you haven't already seen 'Good Slides Matter', because it refers to some research behind what works and what doesn't in multimedia learning, and advises how to build presentations accordingly. There's also some SUPER-ADVANCED MEGA TIPS at the end... :)
Thanks to @girlinthe for drawing my attention to the multicolor search engine - a brilliant tool! Try experimenting with putting in the two main colours of your library brand - you can then do away with templates entirely.