As I was working on a project with DPNs, I decided to share with you all some pointers that I have learned along the way that help me with using them. In the wrong hands, DPNs are unwieldy and awkward. With practice, though, you'll get it!
1. Whenever possible, buy DPNs in sets of 5. Many stores sell them in sets of 4, but don't do it. One of the needles is the one you're working with, so it works much better to have the live stitches will be divided between 4 needles instead of 3. Your knitting is less likely to have "ladders" where the needles join and trying on that sock you're working on will be much easier with that additional needle.
2. Cast on all your stitches on a single DPN. Let's use an example of 40 sts. Once you have all 40 on one needle, start from your first cast on stitch and slip 10 onto each of the remaining 3 needles, letting the needle fall once it has ten. Then you can arrange the needles into a square, being careful not to twist the stitches, and join in the round to begin your work.
3. Beginning of the round stitch markers can be problematic on DPN's. At the end of the needle, they'll slide off. You can choose to move your stitches around so that the beginning of the round starts in the middle of a needle, or (as I prefer) you can use a locking stitch marker and attach it just below the first stitch of the row.
Every few rows, I move the marker up again so I see and feel it coming.
4. I briefly mentioned laddering in number 1 above. Laddering is when the stitch traveling between needles is more loose than the rest of the knitting. It can be unsightly in the finished work, so here is how I prevent it. When I move to a new needle, I work the first stitch and then insert my needle into the second stitch but stop there. I take the working yarn and tug it tight - not so tight that first stitch won't slide on the needle, but firm. I then go ahead and work the second stitch and proceed. Here is a picture of when I tug, sorry it's blurry - 4 year old photographer.
5. I like to have each needle below the needle to its right, and above the needle to its left. This keeps my work neat and laying flat, allowing the gaps between the needles to be as small as possible.
6. One problem I watch for on DPNs is an inadvertent increase between the needles. In the picture below, I found a place where I was knitting the last stitch on one needle and purling the first stitch on the next needle, and I didn't do a good job of making sure the working yarn was in the right place. Essentially, if you work this stitch, it will be a yarn over, making a hole in the knitting.
So be careful when your moving yarn from the front to back, particularly at the join of needles, and make sure the yarn passes both tips of the needles.
7. If I'm working a large cable that spans more than one needle's worth of stitches, I try to put the (or one of the) cable crosses between the stitches. That way you're not moving stitches back and forth from needle to needle.
8. Decreases can cause headaches on DPNs, especially when you have one stitch left on the needle and you're needing to k2tog. Think about the direction your work is headed and divide your stitches as best you can to avoid this. Don't get too hung up on having the stitches divided evenly.
Hopefully you won't be afraid to give the DPNs a try. They're a lot of fun to work with!