I have been knitting (that is, trying to master knitting) for about 8 years now. But silly me, I've only stuck with one "way" of knitting (the traditional continental method). Perhaps because of my crochet background (or not?), I tend to strangle the yarn tension-wise. That has meant it's often very difficult (not to mention time-consuming) trying to slide my needle into the yarn loop while it's on the needle.
Today, in an attempt to fix a completely unrelated problem (uneven tension when I purl vs. when I knit), I finally watched the videos on this site about purling in different ways. One method, the "Combined Purling Method," really caught my attention because I had knitted the whole front side of a sweater using an incorrect form of Combined Purling without even realizing it and it went very quickly (plus, my stitches were very even, but since they were technically "wrong," I frogged the whole thing and started over).
After watching that video, and going to the recommended link which had more information, I'm now thinking: OH! MY! SQUASH!!!! This is SOOO much easier than what I've been trying to do. Why didn't I watch these sooner?
With this method, I have much less hand fatigue, my stitches are almost perfectly even, and I have no problem sliding the needle in where it should go.
So, take it from a slow learner--watch a few of these basic videos to see if any of these methods might help you, too!