N.,
I know it's tough... I wanted to be consistent and do it right too. The sleep issue was one of the hardest for us. My husband and I both would vacillate between consoling him, both in and out of the crib, walking him for hours in the middle of the night and tossing and turning in our bed as he cried in his crib. What a tough time!
I took advice from both sides of the coin- strict regiment moms and AP moms who would do whatever the baby needed. My father told me the best advice, or truest of the truths- Just when you think you've got a routine going with a kid, they go and change it on you.
For me, it wasn't easy to do it, but if our son was inconsolable and would cry even when we were holding him, I'd usually put him down. If he was dry, fed and otherwise pretty comfortable, I'd leave him to his own devices to get to sleep. It was HORRIBLY hard to do, but I figured if he was miserable, we'd be miserable too, but there was no point to escalating it to utter frustration and despair on our parts. A few nights we'd even turn off the monitor because he was just crying his lungs out. Seeing one of us would just make him cry harder.
We did start delaying how long we would go to comfort him- first wait five minutes, then wait seven minutes, etc. I can't remember what this method is called. That seems to work well for us, but maybe he just got the hang of it on his own.
Our son is 9 months now and when people ask when he started sleeping through the night and we answer 2 months, we get a lot of "woah, you're lucky!" Most of the time when he was crying at night it was because of one of the 7 things- hungry, wet or dirty, overstimulated or understimulated, hot or cold, tired or wanted to be held... he wasn't ever colicky, and 9 times out of 10, it was the first two.
Advice for you- trust your gut and take a deep breath. One day he'll be breaking his arm climbing a tree or skinning his knee riding a bike...