I start a conversation but don't take a number to take that further towards the coffee date or friendly date. Case 1 I was sitting in a college canteen where I am doing Ph.D., two girls sit in front of me, as the restaurant was crowded.One married one unmarried.After few minutes I started converting to married about if she is student etc. and Casual talk further....her friend joins in....we have a good conversation....few laughs....eye contact to the unmarried...she was interested in me I could sense...I don't know to what level but yes interest was there....I leave as I have some important work waiting...I say let's meet sometime for tea....realize I just know their names have not taken their number...I am sure they would have given me and met me outside for coffee. Case 2 I am sitting in public transport start conversation with the girl seating next.... she opens up and responds well...have a good few minutes conversation ...her stop comes, and she goes saying goodbye ...she was interested in could tell... I should have taken her number and try to a coffee date.... so next time I will ask for a number or better give my phone and ask to save her number and later call and try for a coffee date. Need advice how to effectively number close.