One rule that is (for me) more important than any else is:
-Don't rush! Play the game slowly, walk instead of run (where appropriate), spend some in-game days doing nothing quest-related, like wood chopping, picking flowers and then experiment with alchemy, go goat-hunting, go admiring women in towns

, take a swim in river / lake / sea, or whatever you like...
Personally, I use wait function when I forge armors, e.g. I "wait" for 2 or 3 hours when I construct an armor or even more. When I read a book and if it's longer, I "wait" 1 hour after reading it - to at least make it a bit more realistic (in real life time also passes when you read a book)
I also usually eat three times a day (if possible) and make sure that my PC gets enough sleeping (7 hrs on average per night) but in case I spend more time awake, then I sleep longer.
Another thing - set limits for yourself! It just wouldn't be possible in real life to carry with you 6 swords, 50 potions + all other items without any backpack or bag. I play on PC so I use a backpack mod which adds a lot of realism for me but until I don't get it, I play with one set of clothes, one or maximally two weapons, few potions and so on...
Also, I never explore every possible location with one character - it depends on my protagonist's ambitions, goals and backstory. Backstory is very important aspect! Create a character with a past and shape his / her actions according to preset moral decisions, beliefs, combat skills and so on...
I think the most important thing is NOT to rush and set limits for yourself. If I remember sth. more I'll post them. I hope that helps a little.