I have a trying time with dpns, too, so don't think you're alone. I prefer to use 5 needles instead of 4 (personal preference), and I have to remember to give the yarn a good tug at the beginning of each needle. Have you worked with circular needles and done projects in the round? It's the same basic principle with dpns. In a straight stockinette pattern, you'll never purl - if you do, you know you've turned yourself around and are knitting flat again.
If you search on Youtube for videos on knitting with 2 circular needles, you'll also get some good visuals on knitting small rounds as you would with your dpns. Different tools, but the same basic technique and the same result.