The same as any location and setting at the end of the day.
As said above getting their attention fast is a key! Totally different environment but as David Stone talks about in his book a fire wallet works well! But really its trying to find something that suits your style and makes them want to see more and interested rather than making them thing wow/how?!
Also I like to keep my first trick really short. Like the D&D style tricks which are flashy but to the point, to keep them interested!
I think one additional thing is making sure people know it's free so they don't think you're busking or begging as I imagine this would put some people off before they've seen what you do and where I live is a very touristy city and I'm sick of people coming up to me asking for money for one thing or another or to sign up for their TV or whatever
Ultimately, experiment with a few things and see what works.
Also a camera works wonders, like a decent quality one with a microphone... People think its actually for something then and at least to me seem much more into it. Note that a cheap, small poor quality will have the opposite effect.