I sometimes see conferences or user groups trying to solicit new, i.e. first-time speakers. It's easy, they say. You don't have to talk for an hour, they suggest. Try giving a short talk about something that you're familiar with.
While this is well-intended, I found that it's actually pretty hard to give a good short talk. I'm wondering if it wouldn't be easier for first timers to start with a longer talk.
