Boo, I never left her to cry it out, nor did I really leave her to cry at all.
At first I put in crib awake, if she cried I shushed and patted/rubbed tummy. Stayed with her through the inevitable wake ups to immediatly shush pat. Around a week I think...a very long week!
Then when she stopped waking a lot after her initial put down, I left the room returning to shush pat if she woke. At this stage I still patted to sleep, for a few days.
Then I started putting her down awake, left room immediately and returned if cried but just layed hand on chest and shhhh till calm, walking away before she fell asleep. Sometimes she'd be crying before I even got to door.
Biggest breakthru was noticing a difference in cries. One was shouty...I left her to it and she'd shut up and fall asleep. One was her having a moan...let her moan for a bit, standing right outside door & she would go to sleep. One was real and I never left her for those. If she didn't really sound too upset I would give it 30 seconds before going in. She's given a lot of love during day and is very secure baby, waking up with a massive smile.
So I guess I did let her shout cry a bit but I felt sometimes she needed to & was never left to cry properly. That worked for us. The book previously mentioned called the good sleep guide helped a lot.