I recall seeing a Pic of one guys hand written cheat sheat of contraolls. He never used it. Possibly because writing it down helped memorize it?
The keys that are the least obvious are the hotkeys which as Invalid_ said can be easilly reached via the esc > controls menu. You will look at it several times. I still find myslelf looking at it from time to time for that ONE KEY I just cant remember. Usually because I re-maped it to be easier in the long run.
after that Its either situational hotkeys (o)pen for window/doors (s)mash for breaking things, and knowing when to do so but especially (e) - interact which can have all kinds of situational uses you might go some time without realizing, like if you ©lose curtains, you can then (e)-interact with them to tear them down for valuable supplies, namely long string. Or using a tool on you like a crowbar/shovel on the terrain around you.
OR using the item hotkeys straight from the (i)nventory menu/ mapping custom hotkeys for them so they stop moving around.