It's easy enough to get IOS's off girls like smiles and eye contact and to ask them questions, but how do you get them to ask questions back to you?

A lot of PUA strat emphasises that you shouldn't ask questions to the girl that involve her life. Once you build attraction and start to build comfort, any questions that she asks you will be an IOI. Have you read any mystery method related texts? They outline DHV methods that will get the girl into you.

a good way could be to tell DHV stories and leave a lot of open ends in them for her to ask about.
however, if you were interesting enough and had enough attraction, the girls would be asking all sorts of questions about you during comfort, with the questions becoming more personal as she gets more comfortable with you. dont forget that once you're in comfort you can also start asking her a few questions about herself, but the key is to not make it sound like an interview and to keep her on her toes. if you ask a question, she'll be more comfortable asking you questions.
mystery mentioned the 3 second game in his book. basically, you ask the girl if she's ever played the 3 second game when you're in C2. the rules are only that you have to answer the question within 3 seconds (this way she doesnt have time to think/lie... she just blurts out the answer) and that you cant ask something that has already been asked to you. i havent tried it yet but i think this might work for you.

exactly! demonstrate higher value!

here are some great examples:

http://ezinearticles.com/?Techniques-to ... id=1422832

_________________
www.bestseductionbooks.com