Most Helpful Guy
Beautiful women are intimidating because guys don't approach them for fear of angry rejection. These women attract many men and have to turn down many of them.
Well-done-up women are also intimidating because it shows that they are confident. Many great guys simply can't go toe to toe with a woman in an initial conversation because the physical appearance is simply a distraction to a guy's confidence.
Now, being friendly as the girls have posted is a start, but a danger (i.e. beautiful women danger above).
Dressing down is also a good thing to do because then the guys you see most often can see your casual side and see that you do know how to have an off-day. The more of these you do, the better you'll also feel about yourself. This will show that you can let your guard down and maybe, just maybe, if there's a guy you like, he may notice you dressing down, and this will trigger a response in him that maybe you are approachable.
Is there a reason you always need to have a 5 star quality appearance in public incessantly?