well, what you really should do first of all is take your tripod and post it in the middle of a crowded plaza where people tend to walk towards you. adjust the tripod so it fits snuggly at an eye-level and then just look through the viewfinder. telephoto lens are best, because beyond letting you get close it also provides shallow depth of field ideal for isolating your subject and also makes people look at it curiously. Ok, then just start snapping away what you want, track people as they move along, maybe even capture more people. this has been the first step. now you have to get out and actually meet people. Step two is two take a picture of a guy you like on the street, because it is motivational and where a normal subject would make you say better not here your other interests help you. and of course the last step would be to take photos of people who are morally indebted to you, say a shopkeeper who wants to sell you something.
one thing however you must never forget: if you smile at a person not only will it make it easier for you to ask him to pose(especially that you're a girl

), but also 9 out of 10 cases he will smile back with a natural smile.
usually people pose because they think that is what they should or, of course, don't know what to do. they are as shy as you but a little proud too. So if at first the expression is not the one you werre looking for (it rarely is) take the shot anyway. That willl bridge the gap between you two. he will get used to the camera and you to looking at him through it. the next shot will be better. But the really
golden trick here is to talk to the person, make him feel like a friend, not a test subject.
and of course try to ask a photographer friend (if wsuch one exists) to target you for portraits for maybe an hour or more, so that you can understand what someone in the street or w.e feels when their pic is taken.
look here how nice a pic gets when you just smile and keep them busy from thinking of posing. the first pic was a disaster of this girl but while walking talking and especially smiling her expression got in the end to this:
hope i helped and that you will lose your shyness as quickly as possible
