We did it a couple of weeks ago at just under 10 months, it's very controversial on mumsnet so you might get a lot of people telling you not to and likening it to child abuse but I felt I had no other choice. We both weren't getting enough sleep cosleeping & had pretty much no routine as he wouldn't sleep in his cot at all even for naps, so I was desperate to do something!
We started off putting him in his cot awake but tired for nap times & sitting in the room with him but quickly found that that kept him awake & he wouldn't settle. So then I decided to start leaving the room immediately, so big kiss and cuddle, "sleepy time now, love you" and lots of affection then I'd put him down and leave the room. The first night he cried for half an hour, but I left it 5 minutes, went back in and settled him (no picking up), then 10 minutes, went back in and settled him (no picking up), etc. He woke up at 1am and instead of bringing him in my bed I did the same thing - it's very tempting to bring them in or pick them up but you need to be consistent to not confuse them.
The second night it took about 15 minutes of crying and he slept right through 7-7 no wakeups (or he woke up, cried for less than a minute then settled back to sleep). The third night about 5 minutes, still sleeping through. This has been very successful for us and I put him down in his cot awake for both his morning and afternoon nap following the 234 nap routine (google it) and he no longer cries. Just snuggles his comforters and dummies and goes to sleep pretty quickly.
Tips:
• I put two comforters, three dummies and a teddy in his cot so he could a) always get a dummy and b) have something to cuddle (obviously doesn't apply if your baby doesn't have a dummy).
•We don't use dummy during the day, only for nap and bedtime so I keep them in his cot and don't leave the house with them (he will sleep in the pram/car seat without one)
•Implented the 234 nap routine and followed a bedtime routine - so bath, massage, bottle, brush teeth, bed
It can feel quite restricting at first so I'd stay in the house for a couple of days while you try it. Your baby might not take to it, but mine did as he used to settle off to sleep no problem but it was me that gave him bad sleeping habits. Obviously if your baby is very distressed or not taking to it then don't persist, they might not be ready.
Also, if baby is teething or poorly then do not try this. My baby got his first tooth over the weekend and was crying in pain, very distressed, so for two days we just had lots of snuggles and coslept (we both barely slept as he was quite bad with teething) but after two days, once his tooth popped out & his teething fever was down we went back to the routine and it still works a treat.
Sorry that is long! It's just so nice to have my evenings back and share a bedroom with my husband that I hope it can help somebody else. It's honestly like a light switch went off and he loves sleeping in his cot now and sleeps right through the night which is insane compared to what it used to be like!