Don’t fail in CSAT is probably the most important mistake to avoid. Been there done that situation so. For that having a strategy by solving a good number of papers even now will help.
Another mistake is that everyone will say that you must sleep 6-8 hours before the D day, but for most of us it doesn’t happen that way. It just doesn’t.
I would say just stop worrying about that and you can still perform the best we need if we had 2-3 hrs only. But thinking that we can’t is worse.