naps sleep training?

my baby girl is an awful napper! once sleeping I used to be able to put her in her crib. then she started waking up as soon as I did this. we then transitioned to napping in the swing. I would have to rock her or feed her to sleep first. this mama is tired of fighting naps! she does well at night...will nurse herself to sleep and then only up a couple times to nurse. she will be 5 months on the 7th of Sept. I have tried to just leave her in her crib and comfort her without picking her up and letting her cry but she gets soooooo worked up and won't soothe herself to sleep. I'm getting extremely frustrated with naps!! any advice on how you get your little ones to nap on their own?