I really like the book "Healthy Sleep Habits, Healthy Child". I got mine when my oldest was a newborn. He is now almost 4 and we have a 19 month old daughter. I still refer back to it every so often when sleep issues happen with either of my children just to refresh my memory.
We use the Cry It Out Method after trying a few other things first. There is nothing wrong with letting your baby cry for a few minutes. We aren't talking hours of crying here, just a few minutes.
With my son I would rock him and sing a few songs to him and then lay him in his crib drowsy or awake for the night starting at about 4 months. He learned to fall asleep on his own. Right at 4 months he started to sleep 12 hours at night on his own so that is when I started to "sleep train him".
With my daughter she started sleeping 12 hours at night at 3 months, so that is when we started sleep training her.
Now at almost 4, my hubby puts my son to bed. They will read a book or two, sing songs, pray, or just talk for about 10 minutes in my sons bed. He gets put to bed between 730 and 830 (830 if he took a nap during the day, 730 if he didn't take a nap) and he knows he is not allowed to come out of his room. He can either read or play very quietly in his room, but he is to stay in his room and go to sleep.
At 19 months, I will rock and give my daughter a milk bottle at about 630pm for about 20 minutes. She then tells me "No" when she is done and gives me her bottle. I burp and rock her and talk to her for a few more minutes and then put her in her crib fully awake. She falls asleep on her own.
There have been and are nights where my kids fight going to sleep on their own and have had to cry it out until they fell asleep. They are totally fine, happy, well adjusted normal kids with no emotional scars from it. The hardest was when we first moved. My son cried every night for hours for 3 straight weeks. The first week and half we coddled and comforted him because we knew he was truly scared from the sound of his cry. After that he was doing the "I just want attention" cry, which is totally different from the "I am really scared" cry. So that is when we started to just do our normal bedtime routine and then let him cry it out for 20 mins, then 30 mins, then 40 mins, then 50, then 60 mins. Each night we added 10 minutes to the time we would let him cry before we checked on him. And each time we checked on him, we would go in, hold him for a few minutes, then put him back in his crib and leave the room.
Both kids get up around 7am.