craftgrrl | Knitting / DPN's question

So, I've figured out how to knit in the round with double pointed needles, but am having trouble once the number of stitches decrease more and more. I find it really hard to continue knitting, everything starts to feel too tight to keep going, and I worry about it looking sloppy. I then get frustrated and put the project down, so at the moment, I have about 4 unfinished hats.

Any tips on easier ways to knit smaller areas with dpn's? Or easier ways to knit the crowns of hats? Any advice would be helpful, as I haven't found a whole lot of useful information online. Thanks!