But I like Pick a Card Tricks
Everyone's been right so far, I'll give my two cents to add on.
I think it's been helpful for me to have 8 or so tricks in my head. A few card, some coin, and some other prop magic (bills, straws, silverware, rubber bands...) and then one or two heavy hitters (that I will more than likely not use).
Those 8 tricks are the core of the act and I do 3-4 of them (usually prepared sets) at a table. If all is going well I can pull out a heavy hitter (Giant wooden Finger guillotine ftw!...) or one of my other tricks that would fit where I am.
It's important to have 2 different sets of magic so you can do tables that are near each other without repeating the same things they just half-way watched over their shoulders.
Time is more important than tricks (as has been pointed out) and time is dependent on more factors than most beginners take into consideration. David Stone's book Close-Up: The Real Secrets of Magic has a lot of practical advice for figuring out how to divide the time between every table and tons of other advice that you'll want to know before doing strolling/restaurant venues anyway...so buy it.