Take my advice for what its worth, as the only one i know who endorses it is myself

You want to stand out but you don't want to be obnoxious about it. Picture yourself being someone else (an adult, more likely, or a young lady, if thats your ulterior motive

See, I can't tell you whether you want to come across as a young professional, a teenage clown, an arrogant showoff, or a colorful trickster. Thats up to you. My advice: pick a personality that mirrors the person you really are inside, and amplify it.
Personally, the little street-jockeying i do (less than three hours or so total) I dress casually and let the crowd around me speak for my ability. anyone can wear a clown hat and goofy bow-tie. Not everyone can perform magic.
More important than costume is appearance. Make eye contact. Be confident. BE YOURSELF. as I said earlier, you can be an amplified image of yourself but you CANNOT pretend to be someone you're not without coming across as artificial and goofy.
again, this is from more of a spectators perspective than a performer's.
as far as tricks go:
AC comes to mind immediately. try a different presentation. IMHO its the best street artists trick. sorry about your sour audiences, but we all have bad days. don't discredit the illusion

coin and note tricks are excellent to know, as props can often be borrowed if necessary. be wary of asking strangers if you can borrow money for a trick "Wanna see a trick? can I borrow a twenty? Okay, Now I'll Disappear!"
any cards-to-pocket routines go over well. I think penguin magic had a trick called mambo number five that got me started with cards in general. it would be great for street magic.
vanishes with borrowed drivers licenses and such might also be entertaining. most card vanishes or productions will also work with a rigid material and its worth considering, as it eliminates any suspicions of a rigged deck.
best of luck, and PLEASE report back often to share any tricks you learn with us.