Has anyone tried sleep training?

Since my little girl has been getting older she has been harder to put down for naps.. So I was relying on the swing. But all of a sudden she is not wanting to nap in the swing. So as of right now I have to put her in her bouncer, jiggle her till she falls asleep and then lay her down in her playpen (she will not sleep in crib for some reason). The problem is I don't want to rely on the bouncer.. I have spoke to sleep trainers and they say the extinction method works best. She is 5 months old now and I think this might just get worse. At night she is waking 2 times to eat and sometimes she is up at 3am to play. It is very tiring. I am wondering if anyone has had any success at sleep training their little one??? If so which method did you use??