Welcome to pherotalk roffa123,
Since you have no problems with girls coming up to you and then carrying on a conversation, i think you should work on boosting your confidence and initiating some conversations as well, because in our society its not entirely normal and going to consistently happen, that a girl will approach a guy. I think you may be missing out on a lot of opportunities where women were into you and you just didnt pick up on it.
When they are looking at you and making eye contact, this is an initial flirting from them when they position themselves towards you they are subtlely telling you that they are interested and are ina way flirting with you. Try to make eye contact with them as well and not quickly look away. Ill give you a link at the bottom of this page to check out some indicators of interest and how to spot womens subtle means of interest.
Looks like you already have a bunch of suggestions that should be very good for your situation and i wish you the best of luck and hope you take heed to the things i have said !