I'm trying to learn to play NL tournaments better now too as opposed to Limit cash games.
I think some things I've found helpful in the earlygoing are:
a) Don't be that aggressive
b) Don't bluff
c) Only go in on sure hands (or as close as you can get)
They seem to help in lasting a lot longer...but as people said above, really depends on the specific situations.
Note: For final tables/cash games, I wouldn't follow any of the above. Play aggressive, Bluff when it will pay off, go for it sometimes
