Do impositions provided by the game options count? Except for my very first playthroughs back in A19, I've always played dead is dead. Now that there is a game option for that, it makes it more permanent, by I still see it as a self-imposed challenge since that is not the default setting.
I also play on 16 hour daylight (I think the default is 18?) which leads to longer nights (sun will not rise until 6am). It always seemed weird to me that the sun in this game rises at 4am by default. That's really not the reality, especially in the region this game is set.
Like others, I also try to avoid the "cheesy" tactics that this game allows, such as nerd polling, or impossible floating blocks. I try to build in a realistic fashion.
I also avoid jumping out of tall buildings, even if I have all the perks that would keep me from breaking my leg.