Twisted stitches aren't strictly related to cables, but this is still a good place to talk about them, because they often are used in a complementary way.
A twisted stitch is typically created by knitting a Western-mounted stitch through the back leg. This causes the old stitch to sit around the base of the new stitch with its legs crossed, right leg over left -- note that it's actually the old stitch which gets the twist, which can be a helpful bit of knowledge if you're trying to decipher from a piece of knitting how it was created, or to count up rows from a twisted stitch. The twisting pulls the stitch tight; fabric with a lot of twisted stitches will be shorter than an equivalent fabric with untwisted stitches, and will have less horizontal stretch. Columns of twisted stitches have an almost braided texture; also, the twist tends to cause the left edge of the column (composed of the right legs which have been twisted across) to lift slightly, which can be used for textural effects, and the resultant sharp lines are often part of the desired outcome.
In the previous paragraph, I specified that the stitch was Western-mounted, which means a stitch mounted with its right leg in front and its left leg in back of the needle, because, as you'll recall from the discussion of combined knitting, Eastern-mounted stitches produce untwisted stitches when worked through the back leg. Eastern-mounted stitches can easily be twisted by knitting them through the front leg -- note, here, that in both cases the twist is produced by knitting into the left leg, with the difference being where that left leg is located -- but it does twist in the opposite direction, with the left leg crossing over the right.
What difference does that make? It could be a lot, and this is one of the cases where the yarn in question is important. Find yourself a piece of yarn, preferably a multi-strand plied yarn, and put a loop of it over your finger. Twist your finger several times and look at what it does to the yarn, and then untwist and twist it several times the other way, and look at the difference. In one direction, this twisting will tighten the plies, so the angle at which they lie across the strand is sharper, and in the other direction it will loosen the plies, so they're almost parallel. In a similar way, twisting a stitch in one direction will tighten the yarn, while twisting it in the other way will loosen it; twisting it in the tighter way gives you a stitch that would like to untwist, which increases the tendency of that upper leg to raise up and gives you a more dramatic look, while twisting in the looser way loses some of that effect.
Most multi-strand yarns for the hand-knitting market are plied in the direction where the yarn appears to spiral upward to the left (I understand from Michele Lock's "Why Ply" article for Knitty.com that this is "S plying", but I am not vouching for the correctness of that statement -- I am not in any way a spinner). Yarn plied in this direction will tighten when twisted by knitting a Western-mounted stitch through the back leg. Singles, on the other hand, are often spun in the other direction -- Brown Sheep's Lamb's Pride is an example of this -- and some cable-plied yarns or yarns marketed primarily as crochet yarns are also plied in this direction. Yarns spun or plied in this direction will loosen when twisted by knitting a Western-mounted stitch through the back leg, but tighten when twisted by knitting an Eastern-mounted stitch through the front leg.
This consideration is an important one when selecting a yarn for a twisted-stitch project; most knitters are going to want to select an S-plied yarn, so that the twist of the yarn and the stitches work together. A combined knitter, for whom it may be easier to work twisted stitches in the other direction, may prefer to select a cable-plied yarn instead. This is not to say that a knitter may not choose to do otherwise for other reasons, but it's something to keep in mind, especially if a project doesn't seem to be working out in an ideal way.
If you find twisted stitches interesting, there's a class of knitting patterns that you may want to look into, which are the reason I chose to cover these topics together: Austrian/Bavarian traveling stitches. In this type of pattern, ribs of twisted stitches travel on a reverse stockinette ground and cross in tiny, intricate cables -- it really combines all the techniques we've been talking about, and as most of the crosses are only two stitches at a time, it's a perfect place to practice your technique for cable-needleless cables. The canonical sources for these stitch patterns are the 3-volume set Uberlieferte Strickmuster, by Maria Erlbacher; unfortunately, these books are (a) in German, and (b) appear to be out of print at this time. If you'd like a little taste, check out Eunny Jang's beautiful little Bayerische socks -- as Eunny herself notes, the 7-stitch large cable (the ribbed rope cable of charts A and C) isn't quite canonical, but they're lovely nonetheless, and will still give you a good sense of what this type of knitting is about. Enjoy!