My job normally is a deskbound one, but this Thursday night I have to present a small, short seminar. It's quite an informal setting (upstairs in a restaurant), but the guests will have paid to attend and so I don't want to disappoint them.
I'm crapping myself. 
I'm trying to write my speeches (I have to give two, each 25 minutes long) but I don't really know how to write a "speech". I've only written features and books! I'm finding what looks/sounds good written down actually sounds shit when said out loud!
Plus, I want it to be informal - lots of Q&A - but does that slow things down to the point I'll have to hurry people along so I can make my next point..?
I'm so inexperienced with this, I don't even know what questions to ask you all. So if you've ever had to do this and can impart ANY ADVICE AT ALL, I'd really appreciate it. Thanks!