The two additional thin gs that I do ( tips picked up from PPRUNE, thank you very much) are to not only figure out where my nearest exit is but to familiarise myself with which exits can't be used in water ditchings (it varies a lot from plane to plane)
Also check that there is indeed a life vest under my seat.
I couldn't help thinking on my last commercial flight about all the useless stuff they tell you (how to work a seatbelt) and all the useful stuff they don't ( which exits to use, how important it really is to get the oxygen mask on quickly)