Hello friend. I'm also going to BSOP Millions in SP. Just went to WSOPC at Unique Hotel and played the Brazilian Storm. Not so good for me, but the experience was amazing, I really recommend you.
I can tell you that you have to put in your mind the opportunity to play in a huge event, so u have to enjoy yourself, the result is consequence. Play the same game you play on the other places, do your best. In my case, the buy in was a little high, so it can make influence on the game. (the best comment I can do)
If it is not a problem for you, there's a nice chance to pick some chips and get some money.
Remember that this event is not only for playing, is also to meet some poker players, famous or not, to chat, maybe have a drink and make a lot of good photos.
When you get there, just make what you know, and everything is gonna be okay. GL.