So I've been single all my life and in general have a very hard time getting the opposite sex to think of me as having romantic potential. While I'm chalking most of this up to personality, I think some physical appearance comes into play for a subset of girls (I'm 5'4" and look roughly 6 years younger than I am). In normal life, I don't really encounter many girls working as a software engineer and haven't since HS (college ratios were roughly 20:1 in most CS classes). All this to say, I don't get a chance to practice being anything other than a friendly professional very often.

In the past year, I've turned to several online dating services for more dates: OkCupid, Tinder, Coffee Meets Bagel, and even Reddit's /r/r4r. As a result of these using these every day I pull in about 2 dates a month. Once on the date, I seriously don't know how to act. The conversation flows like it would with any friend but that seems to be a real problem in and of itself (i.e. it just feels like talking to a friend). Conversation topics have been wide-ranging from jobs, hobbies, college, interests, favorite music, favorite coffee, how we dream about having different lives, etc. So I don't think awkward pauses are an issue...

I'm no expert at body language but I can see a "I'm bored" look on just about anyone and by the end of the date the laughing turns to this. There is no lingering talk outside of a bar or restaurant...just a quick hug and her making a beeline to the nearest cab or car. Furthermore, future texts usually go unanswered...

So any suggestions?

tl;dr I'm inexperienced with flirty, romantic conversation and women never want a second date with me