• I always joked about pick-pockets until I was pick pocketed. Then it wasn't a joke anymore! Buy a Flip Belt and put your phone and valuables inside of it. Keep it tucked away under your shirt.
• Bring minimal ID and Credit Cards. Meaning your DL, medical card, and ONE Credit Card. Nothing worse than having to call multiple banks, go to DMV, and call DHS (Sentri/GlobalEntry) 'cause your wallet was pick pocketed. Also set a reasonable daily spending limit.
• Turn on lost phone tracking. Thieves will turn off your phone. However, honest people will leave it on and try to get it back to you!
• Phone reception sucked in 2019, since there's so many people on site. Enough people brought GoTenna's and they worked great all 3 days. Split the cost with a friend.
• Please pretend the security line is like the TSA line. Place all your stuff in a clear plastic bag. Take the plastic bag out of your pack for security. Simply place it back in once you're clear. Use it later that night for other things. It helps speed everyone along.
• Those head mounted lights work great. Not only for having a source of light, but also when you go to the restrooms. Just wear it around your neck when you need it.
• Want to go minimalistic? A CammelBak Rogue and FlipBelt is really all you need.

I suggest the flip belt! It's almost kinda like a fanny pack except it's flat and much more discreet. They come in different sizes and colors. I wore it a lot before I discovered workout pants that had pockets in them.

I've had good luck with the FlipBelt.