I did pretty much the same thing as Trish with my first two. Gently taught them to self settle over a period of time using the same techniques. DS1 was not a good sleeper as a younger baby although he did learn to self settle quite early - the issue was he had a lot of trouble resettling himself once he woke.

I've struck it lucky with DS2 - he has been self settling from very early on, probably about 6-7 weeks. It wasn't anything I did, I assure you! He has just always been able to calmly put himself off to sleep, I sometimes sit and watch him cause I'm so amazed by it! LOL.