I am currently looking for ways to improve my presentations. I think these 30 minutes that @chrisbrogan and Nancy Duarte prepared for you and me might help you a lot in improving presentations. Just like @chrisbrogan said on the video even if you can watch the first 5 minutes it can be of much value.
Are presentations working for you?
Are there any other business issues you are trying to work with? Maybe joining in on the conversation Kitchen Table Companies (Affiliate Link) might help you get some of your questions answered.