I feel your pain. It was about 14 months ago that I was in the same boat, I felt like I was doing something wrong. I just couldn't get DS to settle in a pram or bassinett during the day, he slept pretty well at night once he was down, but had the evening unsettled period.
I resorted to wearing my DS in a sling during the day, he would spend most of the day sleeping, I just got on with what I had to do, with him strapped to me as best I could.
I found covering the sling in a light wrap when I wanted him to settle also helped. On top of that DS was gennerally only happy and settled when there was constant movement. None of this helped when the evening came around. I was always relived when DS finally settled. I would even eat dinner with DS in the sling while jiggling from one foot to another. DH would take his turn when able to, though DS would still settle better for me. I was so tired by the end of each day. This continued for a few months untill DH found that DS had started being more content lying and even sleeping for short periods in the pram, and without the constant movement! This was at about 4 months of age. I still found it almost impossible to get DS to sleep in his cot till he was 6 months. I just kept trying, then resorting to what I found worked, which was in his sling or walking with the pram. It was only after 6 months that I started having success getting DS to sleep in his cot during the day, now he goes to sleep like and angel in the morning, he still fights the afternoon sleep but will nap in the car or pram. Otherwise it usually takes 2 goes and alot of patting a shhhing. He still goes to sleep well at night, usually waking about once a night then waking for the day anywhere between 5am and 6.30am. The 5am day startes are an effort, but we get through them 1 day at a time. He also still has the odd night where wakes and refuses to go back to sleep, and we spend the next hour in tears.

I guess what I'm trying to say, I had so many doubts, is he too hot, cold, wet, hungry etc... trying to eliminate each one and still nothing seemed to work. I couldn't figure out what was wrong. Just keep on trying, what worked yesterday may not work today. It drove me batty. But eventally you will develop your own communication and things will start to become easier. Motherhood is a damn hard job, nothing can really prepare you for it. But you are doing a good job, as long as you keep trying. Do what works and you will succeed.