The shadow wraps method of working short rows - as unvented and blogged by Socktopus - makes for clean turns, with no holes or bumps. Rather than wrapping the stitch, you'll actually add a new stitch - a twin stitch, or a shadow - bundled with the old stitch (the one you're supposed to be wrapping).

Here's a video tutorial; scroll down for photos and the written how-to, along with animation clips from the video (or see the video on YouTube here)...

wrapping + turning into a knit stitch

stop when your pattern says to "wrap and turn" or "w+t" - the next stitch will be the stitch you'll make a shadow wrap into

(if your yarn is in front, then move it to back, as if to knit)

stick your needle through the lower stitch below that next stitch, straight through from front to back - lower stitch means the stitch from the row below, which the stitch being shadow-wrapped is coming up out of (you may need to lift it up a bit through the back, like the animation shows, to be able to get your needle in there)

knit a new stitch through that lower stitch, leaving the first stitch (the one you're meant to be "wrapping") on the left-hand needle the whole time

(now you have 2 stitches coming out of the same lower stitch - the original one on the left-hand needle and the new one on the right-hand needle)

slip the new stitch over onto the left-hand needle, without twisting, and turn work - you are now ready to work the next row (photo to the left is after turning)

important: after "wrapping", the 2 twin stitches you'll have, coming out of the same lower stitch, are to always be treated as 1 single stitch - when counting stitches, they count as 1 stitch, and when working back over them, knit or purl into them together as 1 stitch (this is working the wrap together with the wrapped stitch)

wrapping + turning into a purl stitch

stop when your pattern says to "wrap and turn" or "w+t" - the next stitch will be the stitch you'll make a shadow wrap into

if the yarn isn't already in front, then first bring it to front, then slip stitch to the right-hand needle

grab that stitch's lower stitch loop with the left-hand needle - lower stitch means the stitch from the row below, which the stitch being shadow-wrapped is coming up out of...

...and purl a new stitch through it, making the shadow stitch

slip the twin stitches together back on to the left-hand needle, and turn work

note: if you are making stripes, the wrap sometimes may look better if you move the yarn between needles to back before slipping the twin stitches onto the left-hand needle (before turning) - if your wrap/colors look bad after working a shadow wrap the normal way, then try that out and see if it looks better

important: after "wrapping", the 2 twin stitches you'll have, coming out of the same lower stitch, are to always be treated as 1 single stitch - when counting stitches, they count as 1 stitch, and when working back over them, knit or purl into them together as 1 stitch (this is working the wrap together with the wrapped stitch)

if you need to wrap a stitch a second time, work exactly as the first time, making 2 twin stitches, or triplet stitches - this is not included in the video (since nothing special is done) but here is an animation of a purlwise double wrap