I often have trouble getting a restful sleep. I've never slept much, most of my life. Around the time I was 11, I started staying up all night during the summer because it was easier to sleep when my body forced me to do it. By the time I was 13 or so, I was staying up all night even during the week. It was not unusual to be up 50 hours straight during the school week.
So, in other words, it never really got easier for me. I do sometimes toss and turn so much that I get up out of frustration. I normally go into work at 5 AM, but have gone in as early as 2 AM when I cannot sleep anymore. I find the magic number of sleep hours for me is about 5 or 6, anything more or less than that and I have a bad day (unless I went to sleep from exhaustion, in which case about 10 is good). Having a kid made it a bit easier to sleep, but only because I am that much tired each day... If I make the mistake of consuming caffeine or even something high in sugar within an hour or two of going to bed, I feel strangely compelled to move my legs every few minutes which drives me crazy. Despite knowing this, I still make that mistake every now and then.
I once resorted to taking some of those over-the-counter medications that help you sleep, but I am very afraid of developing an addiction to them.