Hi P.. Your little one is a young to develop structured sleep habits - right now. I would take notice of what DOES make her fall asleep and use it to your advantage.
If it is nursing, then nurse her, when she falls asleep, jostle her a little so she is just a bit awake, then put her to sleep. Stay with her until she falls all the way back asleep. You can pat her, talk to her, etc, and even pick her up if you need to. Once she settles down and is almost asleep, put her back down. You may have to do it a few times, and even resort to old ways to get her to sleep, and then try again next time. Each time it gets better.
I started at about 8 weeks and my daugher is now 14 weeks, and I can plop her in her crib after feeding her in the middle of the night (if she even wakes up), and most times she will go to sleep all by herself. AND she was colicky!
The book that helped me the most was 'The Happiest Baby on the Block.'
This is a NO CRY solution. And it worked like a charm!
It tells you how to re-create the sensation of the womb for the baby so they feel cozy in their own space. He also gives advice on weaning babies off of sleep props and it is not hard to do.
I also have made my daughter's crib a fun place. I play with her in it everyday so she now loves her crib. I never let her cry it out because - one - I could not stand it, and two - I had a friend where it backfired, and her little one was petrified of her crib after a bad crying session.
For me, my daughter loves to be bounced on my knee to go to sleep for naps. At first I had to do it for 10 minutes, and got it down to 2. Once she was just about asleep, I put her in her crib, and talked her to sleep.
Now I put her in her crib holding her and jiggle her a little bit, then just talk to her until she is asleep. The entire process is down to under 5 minutes. I know in the next month I will simply just be able to put her down for naps without any added assistance. Besides I like giving her an extra cuddle before sleep!
I hope I have not overwhelmed you. But do NOT worry about how your baby goes to sleep - getting her to sleep is the most important thing.
Sleep training now at 8 weeks is a great thing to start, but if it does not work right away, don't fret, it WILL day by day. She is too young now to know any better, and it will just stress you out.
Please feel free to ask me any more questions!