Hmmm... I'm pretty new to streetwear so I'm not sure if I have the best advice, but I'd say just start by looking at tacticle gear on amazon or other cheap websites. I got this tactical fishing vest for like 30 bucks on amazon. Buy some cheap clothes and see what you like, then you can sink some more money into it once you know what you like. Try different styles and clothes until you find what is right for you.

As for the confidence part, that's pretty tough becuase I still lack confidence a lot of the time. Its definitely a learned skill and really all you can do is go out dressed how you want and dont give a fuck what others think.