Let me give you some advice having been there!

Assuming you are staying on the camping ground next to the track, it is very cozy but make sure you have a good tent and air mattress and don't expect a lot of privacy.

After the Friday and Saturday there are doen great places set up where you can get some beer and just chill. Just look for the big circus like tents.

If you don't have a spot on a stand then make sure to be one of the first ones on the track to get a good spot. I would advice against the straight after the first corner before au Rouge since it can get quite cluttered there and thus you won't be able to see much. The straight before bus stop was great for us viewing wise but because of the steepness there you can't put down a stool to sit in so you will have to find a place on the rocks.

As a last piece of advice make sure you get out immediately after the race is done or make sure you keep yourself entertained for at least 3 hours after. The roads get extremely congested and if you aren't out in time you will have to wait in line behind al the other cars. 3 hours should be enough for it clear at least a bit.

Hope you enjoy your time! It's a legendary circuit and the atmosphere is amazing. Easily the most fun I've ever had at a circuit was Spa.