Whilst approaching per se may not be creepy, if you're approaching girls at nights in quiet streets, you're going to come off quite creepy. I'd be a little bit suspicious if a girl came up to me at night on a quiet street and started trying to chat me up - I'd be thinking "is she distracting me whilst someone sneaks up behind me" or something like that.
If you're doing night time, go to the busy streets (makes more sense anyway - more girls there) and the girl isn't going to get freaked out - you're just 2 people walking down a busy street with loads of other people and you decide to stop. It's less threatening.
Or of course go into clubs, bars etc. There isn't one particular place that you can or cannot chat to girls, but use your common sense - you want it to be as less threatening as possible. A quiet street in the dark is pretty threatening from a girl's point of view.
The newbie challenge is great for getting people out of their comfort zone. It's by no means going to get you laid though. It's probably more likely to make you new friends or new acquaintances/contacts. Once you've got the balls to go out and chat to anyone, then it's really all about sexual escalation. Having the balls to chat to a girl "gets you into the game" if you like, but then you've got to have the skills to stay on the pitch before you're substituted off!
One of the biggest things to do here is just to have a sexual "frame". Think of yourself as a sexual man (note; not sexy, but sexual). I'm sure you've got a picture in your head of a sexual man, the sort who is always touching women slightly suggestively, who has got the sly knowing sexual smirk, who chats to women and then brings out the raised eyebrow or whatever. Well, some of those images are a bit too Hollywood movie made up. But that sort of presence and thinking is what you should have - think of yourself in that way, and make a conscious effort in your head to try and act in that sort of way whilst chatting to girls, and you'll start to become more sexual with them (again, learning curve, sometimes you may come on too strong, other times you won't come on strong enough, experience helps you learn and adapt in the future).
After that mental issue, then it comes down mostly to touch. If you're always stood 5 yards away from the girl throughout the conversation, with a drink up against your chest, and your body sort of looking like you are nervous and wanting to get away, then you might get a friend of acquaintance out of the conversation, but you're not going to get laid. Check out majikal's guide to kino on this forum, and there are a number of other decent ones dotted around too. Basically, in your position now, start small. Just touch a girl like shaking her hand when you meet or putting your hand on her waist/small of her back if you're "ushering" her through a door. Then work up to more sexual touching when you're comfortable with touching people naturally in a non-sexual way.