First things first - don't use this font in your presentations & even while posting on CE Forums! "Presentation" matters!
Okay, now coming back to your question - its difficult to answer in one post. However I recommend that you go through the following online presentation on Slideshare. Its called "Death By Power Point". There's lot of good advice in the presentation -
http://www.slideshare.net/thecroaker...-by-powerpoint
Secondly, know your topic well. That's a must! Keep the slide count to minimum and let people listen to you - not read out the slides. If your slide contains everything that you want to say, your presence has no impotence.
Engage the audience - another must. Ask questions and let people ask questions to you!
These are just starting points. Presenting yourself well in seminar requires practice & some experience. Just be confident & cool.
Ask specific questions if you have any.
All the best!