When we had our first born, advice was to wake the baby for feeding so they get used to regular routines. We did this once and he screamed for the entirety of that day so we just fed him at irregular intervals but tried to ensure he still got the right number of feeds in a day.
When we had our second we were told not to wake her. But when she did wake she was so hungry she would have a screaming fit so we learned she preferred to get woken for lunch.
Moral of the story: try as hard as you might to generalise child rearing, they'll always find a way to contradict good advice.
I have two kids and they are about as different as two kids can be. They are truly the inversion of each other in every way. There's no way to generalize, what works/worked on one would never work on the other. The only exception (sounds corny but it's true) is loads of love. But I don't need a book to tell me that, though sometimes a reminder..
This might sound a bit callous (and I know it's more left field than callous but it's my only entry point to this topic) but your story kind of reminded me of a time I visited friends for a weekend at college. A friend of theirs had a new born litter of 1/2 Black Lab 1/2 Pit Bull puppies (the cutest, jet black pups) and my buddy and his girlfriend adopted one, Kujo.
Their goal was to get their new puppy used to being and sleeping alone by making sure it slept outside of their bedroom every night. This was the second weekend they had the dog and I, of course, was outside of their bedroom on the floor. The cold carpet. The living room was the only other room besides the bathroom, which we all wanted to keep dog free for everyone's convenience, in their small college apartment. I was told to try not sleep / cuddle with the dog overnight, but not sternly.
I'm a light sleeper as it is and after about 15 minutes of listening to the little guy cry and whimper I caved in figuring one night of sleeping cuddled up with me couldn't ruin a K-9's entire life of attachment. Plus I was on the floor and as you can tell I'm soft as it comes with animals and children.
I'll never know whether my softness that night ruined Kujo's sense of attachment but I will tell you right now, as someone who has always wanted kids I can't imagine I'll be able to keep my own flesh and blood at a distance while they are crying and calling out all night long :*(.
I have so much respect and am in awe of parents of all types. Keep kicking butt!
It's not easy sometimes but you do learn the difference between kids crying because they're in distress and crying because they're just being stubborn. The real difficulty is when they're distressed but "tough love" is exactly whats needed (eg you're example of getting them to sleep in their own bed).
What I struggle the most with is when they actually put a logical argument forward to get their own way. My eldest is not long 4 and he has already been putting some pretty intelligent counter arguments for why he should get his own way for about two years now. Sometimes I cave even if I know he is just arguing because his points are so well formed that I simply cannot argue back (plus I never want to stifle a kids ability to examine and deconstruct the world). My wife often calls me a big softy for that.
Ultimately though, my wife and I compliment each other in different ways so where I struggle with parenting she excels; and visa versa. I don't even know how single parents cope because I know for a fact I wouldn't.
This is why advice can still be useful, but you need to understand that every piece of advice only works for some kids, and not all. You still need to find what works for you, but it may help to have some idea of what the options are.
When we had our second we were told not to wake her. But when she did wake she was so hungry she would have a screaming fit so we learned she preferred to get woken for lunch.
Moral of the story: try as hard as you might to generalise child rearing, they'll always find a way to contradict good advice.