I really do think it was the long hard bit of teaching to sleep with shh/pat that made the difference with my dd. We did it for every nap time and for bedtime. For bedtime, she got it first (probably around 8 weeks we started to lessen the shh/pat time, and by 10 weeks, she was going down on her own), with naptime, it was probably 10 weeks before we started to lessen the shh/pat time and a couple weeks after that before she was down without any shh/patting for all 3 naps (she did the morning nap first, and then picked up the other two). Now she always goes down on her own (no shh/pat), and our on again, off again battle is with nap extension. Here's what we did:
wind down - upstairs, diaper change, swaddle, close blinds, sit in rocker, read a story, rock a bit and talk about naptime, naps are good etc., put her up on my shoulder, start shh/patting until either she was calm or was arching her back and kicking, then put her in the crib on her side and continue shh/patting til she closed her eyes. In the beginning, we'd keep shh/patting for 20 min after she fell asleep, then we'd gradually taper off the shhing and then the patting, and then we'd leave. Gradually (over a period of weeks), we'd lessen the time we stayed shh/patting in her crib after she fell asleep. Sometimes, it would take us a LONG time to get her to sleep in the crib, often we thought she was asleep, so we'd start our "20 min", only to have her wake and we'd start over. We'd do 40 min at a time, if she was still awake, we'd get her out of the crib, sit in the rocker and rock for 10 min to take a break, then back at it for another 40 min, then we'd just start her next EAS cycle if she hadn't gone to sleep yet. It was hard...really hard. But you have to be committed to it going in. If you can't do it for every nap, it will take longer. But I would commit to doing it as faithfully as you can for as many naps as you can. Usually, we were way more flexible on the catnap. The first nap is usually the easiest to get first (after bedtime). I remember my mom sitting down with me and dh when we were really frustrated saying "we can do this....we've worked so hard, and she is getting it, we can't give up now or all that hard work is for nothing". I found the less I wondered "how long will I have to do this" the better it went for me. I had to say "this is how it goes right now....it will pay off, right now it's just going to be really hard....she's just a wee thing and doesn't know how to put herself to sleep" My whole life as a parent is full of teaching her things, and it started with sleep training.
Please hang in there. It is hard. But I can honestly say that it was completely worth it. I have a baby who goes to sleep on her own without CIO and has since she was about 3 mos old. Not a lot of moms can say that. It does work!