Arm yourself with all the necessary information. Research the plan. There are new and old versions of the book and they differ in some things.
Once in cruise, figure out what works for you. If you've a lot to lose then it's worth your while getting this bit right and you'll have the time to do that. I've eaten things, strictly speaking, I shouldn't be, but I lost weight every week and I never put myself out of semi ketosis.
Don't be too hard on yourself. Set out to stick to this at least 95% and you'll do well. If you fall off the wagon, let that go and get back on.
Come on here and vent, share successes, look at the before and after photos....
I honestly never thought I'd get this far, but almost 4 stone later....here I am!