I know it's an extra step on an already big leap you're taking, but talk to people while you're there. Make friends. Seriously, it's very easy to get into the habit of just showing up, holding signs, being loud, then going straight home when it's over. It took me 4 years of doing that to actually start conversations with other protesters and join an organization. Now I get to be part of a community and it's so much better when you're working towards goals with comrades than acting alone.
Don't do anything illegal your first time, especially if you're alone, or anytime for that matter naturally, you know the thing.
Don't separate yourself from the crowd. Cops will sometimes target people outside the mass to present the image of a crackdown without targeting particular blocs because that's riskier.
Stay safe.
I just realized you didn't ask for advice. Sorry about that, but hope you enjoy and it goes well!