Sacha - this is from the Tweddle brochure for babies up to 6 months old

Place drowsy but awake baby into cot and leave room
If starts to cry wait 20-30 sec
Enter room and commence settling techniques with baby on back - one hand on chest and patting hip
If baby doesn't respond turn to face away from you, roll back once settled or deeply asleep
If crying continues after about 20 minutes pick baby up, calm her, wait for tired cues and try again!

We could never go 20 minutes! They suggest to just go as long as you can tolerate and when they are on the down part of a cry stick the dummy in and see if that works. At the start we only got to a couple of minutes before the dummy went in! Only ever got to about 10 minutes of crying and had to pick up! A good test is to see if she stops crying when you pick her up, if she does then you know there was nothing really wrong she is just protesting. Keep in mind the nurses tolerate a lot of real screaming which helped me to know i wasn't being a bad mother!

Anyway, do what you think is best for your bub!! You know her the best and everyone is different.