I think the proper way to increase the number of questions is to get more users.
We want real questions for real problems from real users. We want those users to see the answers and learn from that. If they find this useful, they will continue on and tell others about it as well.
Our questions per day is going down because most of us here are experts, and we have more solutions than problems. We will soon need to attract more of the real folk and get them to participate by asking about their problems.
So instead of spending your time trying to think of questions to ask, I invite you to spend your time publicizing the site. Head over to Coordinating Publicity and do your part.
If you frequent ESOG, then why don't you add a post there and say that you notice all the unanswered questions at ESOG. Tell them there's a new Q&A site that has experts there that will attempt to answer their questions for them. Doing so might get a number of them to come over and trying it. Just make sure you make it a personal-type invite and nothing that looks spammy.