I've asked this question before, apperintly it was in the wrong topic.
anyway, should I use my most visual trick first to gather people around, or should I use it last so I have a good climax.

I would use it last. You can gather a crowd with a TT and a small 6" silk. I might also recommend buying a small sound system and playing some music on it. Then all you have to do to gather a crowd is stand behind your table and wait while the music does the work. Hisonic offers a great little PA system that includes 6 microphones (all wireless), a battery operated speaker, and an ATA-like case to carry it all in.

Street shows (different than Blaine style "Hit and Run" magic) tend to be in three phases. The general consensus is that you start from nothing, gather a few people with things like TT, card/coin flourishes, etc... , and hold them there with your "opening show" as you attract and form your "crowd" with the promise of something spectacular, before moving on to the "Big Event" whether it's a straitjacket escape, Linking Rings, Cups and Balls, Rope thru Body, whatever. The last one has to play "BIG."

Sure, a well executed card sleight might be "visual" to a few, but if it doesn't get the whole crowd on your side you risk going home hungry.

You were asking about where to place your "most visual" trick. What would that be? That would tell us a lot. Tell us what tricks you have in mind for your show, and someone here might help you structure them properly for street work.

It depends on what kind of show you do.

if you are the Cellini type (table cups and balls / 15 minute show) the way to go is what DAVE said.

if you are a circle show (30 minute show build up) you have to start with YOU. so talking to the people / make them get interrested in YOU and then start building.

Exactly! That's why I asked what he planned to do. Even Cellini's show pretty much fits into my outline, just that the "middle show" is much longer.

Well,
my most visual trick is to swallow a balloon and puke up a balloon animal.
I've seen Thomas Medina and Steve ferson use this method of swallowing a long balloon, I pretend to puke into a paper bag, pop the bag and pull out a balloon doggy (this was popped and restored doggy I saw Jeff Hobson do on his dvd).
sounds weird but everyone who's seen it loves it. my other tricks were card tricks, maybe floating cigarette, maybe restored soda can.
it should be about 10 min altogether, it has to be short because it will be cold outside.

Based on what you just told us:

I'd definitely save the balloon gag (no pun intended, really!) for last. Play it up and mention it frequently during your crowd building phase. I'd forget the soda can. It's hard to set up repeatedly, and only really plays well to a few people. Nobody's going to believe that the crushed can that you provided is anything but a "trick can" of some sort. Card tricks could make a good opener, as you involve more and more people, followed by the floating cigarette. The balloon swallow can be played up to take up the whole last half of your show time, after you draw a suitable crowd, of course. Play up what you're about to do and maybe try an early hat pitch.

Whatever you decide, do what I learned this year, and JUST DO IT! You'll know soon enough what works and what doesn't.