Ahh. There's SO many things I could put on the list of 'what not to say.' But I won't bore everyone with that.
Honestly, if a guy shows interest in me, and we start talking, I'd appreciate not being asked for my number right away (I agree with you Orange_23.) It makes it SO obvious what it is you're looking for. Learn the art of conversation first!
Also, when striking up a conversation with someone new, it should be an even 'ebb and flow' if you will. Chances are, if I'm one-wordy, its my way of telling you I'm not interested without being too rude and upfront about it. In regards to the ebb and flow, make sure you don't go on about yourself forever. Trust me, when we first meet you, we don't want to know about your childhood dog, your Aunt Edna, or your high school bully. Stick to common topics, things that most people will have an interest in. Not everyone will be as excited about your '69 Mustang or your '04 Harley.
Facial and body language are a HUGE indicator.
Basically, as they teach in sales, K.I.S.S, keep it simple, stupid! Not too overbearing, simple conversations, and progressing from there will earn you my digits.
Side note: I went through this whole process with someone and gave him my number. As I was walking out the door, he texted me saying 'I miss you already.' OK. Obviously everyone here knows not to do that. I just got reminded of that incident, and felt like sharing with the class :banghead: