Here's another idea. Say something funny to make her laugh. Then comment on how cute her laugh is. That'll be easy to segueway into asking her if she's ticklish(even though you already know she is) because you want to hear her sexy laugh.
Also when you're sitting next to her, maybe casually stretch your arms over your head(as though you're tired, or relaxing) which might tempt her to tickle you, giving you an excuse to tickle her.
There's lots of ways you could "get" her, but if she's ticklish and loves it then it shouldn't be too difficult. I know you're going to have a great time.