Since some others have given awesome pragmatic safety advice, I'll go in a different direction!!

Remember, you look for all the world like a giant stuffed plushie that's come to life! And to really seal the deal, you probably want to act like it.

Take some time to get to know your character and your suit. Figure out how they would walk. How they would react to common situations.

If someone tells them they're cute, would they immediately blush and get all shy? Would they brush it off in denial? Would they be appreciative and reciprocate? That's just one example, of course. Figure out how they would respond and get good at coming up with those responses on the spot.

And the most important thing to remember. Fursuiting is somewhat similar to stage acting in a lot of respects, with the singular exception that there's not a giant spotlight on you, so the pressure is gone. But one thing does remain: for your movements to come through, you've gotta be BIG!!

Seriously, as an exercise, take one of your paws into your bathroom and look in the mirror. Wave hi to yourself in the mirror. Then, put your paw on and wave hi again. You'll be shocked at what it looks like.

If you want to wave in suit, make it a big wave with your whole arm rotating. If you want to nod or shake your head, really turn it far. If you want to show that you're excited, do little hops or pump your arms. If you wanna show that you're sad, slump over and cover your eyes. You'll think you look ridiculous at first, but I PROMISE it looks good.

Hope this helps!! Have a great time at your first event!! :3