Hi Leah4
I taught my boy to setle himslef to sleep at about 4 mths, 'cos up until then he had napped in the cot but I always let him fall asleep on my shoulder and then put him down. This was starting to take longer and longer so I decided it was time he learnt to do it on his own.
I started by getting him a mobile and some toys in his cot, and putting him in there for a bit to play when he was awake. I'd tried to put him down awake before and he'd got a bit scared of the cot I think, and would cry as soon as he hit the mattress, so I wanted him to be happy in the cot and realize it was a nice place to be.
Once he was happy playing in there and I knew he wasn't scared, I made the room dark and put a lullaby toy on, and cuddled him until he was nearly, but not quite, asleep. Then I put him down - he cried so I put the dummy in his mouth ( he hadn't really had it before but he took to it quite well after a few goes) and I held his hands to stop him flailing around, and did lots of loud shushing. I didn't pick him up again, as he was fairly calm with the dummy, but I stayed with him, shushing and holding his hands until he was completely asleep.
I did this routine (room dark, lullaby, dummy, hold hands, shush) for every single nap for a couple of days - he got better every nap and hardly cried at all. Then I stopped holding his hands and shushing, and by the end of the week I could just pop him down with the dummy and he'd sort himself out.
Now, a few months on, he is starting to go off the dummy on his own accord, so we only uise that maybe 50% of the time, but he's certainly not addicted to it, and settles himself really well.
I don't know if this will work for you, but it might be worth a go - a friend has had success with the same sort of thing. At no time are they left on their own, but they learn to fall asleep without help from you. Some would say you shouldn't use a dummy but I found them great!!!
Good Luck with everything!!!