arrive early, security is rigorous and they'll go through every person's bag, plus metal detectors, wanding, etc. you're allowed to have a backpack though as long as it's not ginormous. it helps with any swag you might pick up during the day as well.
they do permit liquids and their containers. I recommend bringing a big vacuum insulated water bottle filled up with ice, you'll be hitting the filtered water fountains frequently. and pack the strongest sunscreen you can find, sunglasses and hat...preferably wide brimmed, you won't really care how uncool you look after sitting in the desert sun for a couple hours. you can even try bringing a sports towel and soaking it in water to drape over your head/shoulders for when it really starts scorching.
check the posted practice schedules for when your favorite players hit the courts. this is as close as you'll probably ever get to them and it's fun watching the speed of their hits at ground level. the biggest names (Fed/Rafa) will practice on big courts, and fill every seat so if you want to catch them you have to arrive minimum half an hour before they do.
be prepared to spend lots while you're on the grounds, but it'll be worth it. Indian Wells has the biggest and best tennis pro shop I've been to at any tournament. the food is expensive of course, but most of it is delicious, and you can go anywhere from quick takeout to fancy sit-down sushi or italian.
on your days away from the grounds, hit up the Palm Springs Aerial Tramway, Joshua Tree National Park, do some outlet shopping, and take it easy by the pool. downtown Palm Springs has many excellent restaurant choices. I recommend booking a table at Birba for some top notch pizza.
here's my photo tour from last year:
https://forum.calgarypuck.com/showpo...&postcount=638