8 month old wakes the second I put her down

The wait-and-pick-up approach saved us at around 7 months. Put her down drowsy but awake, and if she cries you pick up to calm, then put back down. It's slow and your arms will hate you for a week but it taught her the cot isn't a scary place.

Try warming the mattress with a hot water bottle before the transfer (take it OUT before she goes down, obviously). The cold sheet was a huge wake trigger for ours. Game changer for like £4.

Honestly the drowsy-but-awake thing never worked for us, she'd just escalate. What did work was putting her down fully awake at the start of the night and staying beside the cot with a hand on her chest. Took about 10 days to fade out.

Are you keeping a hand on her chest for a minute after she's down before you sneak away? That pressure transition really helped our transfer. Also how long has the awake window been? Overtired made our put-downs impossible.

UPDATE from OP: the warm mattress tip plus putting her down properly awake instead of asleep was the combo. Three nights of protest and now she rolls to her side and goes off on her own. I cried (happy tears). Thank you all.