LT: Leave the first stitch (or next stitch to be worked) on the left hand needle. Insert your right hand hand needle knitwise (front to back) into the second stitch on the needle, knit the stitch but do not remove from needle. Bring needle forward and knit regularly the first stitch on the needle you didn't work yet and slip both stitches off the needle.
RT: Leave the first stitch on the left needle. Insert knit normally, but do not remove stitch from needle, knit the first stitch, then remove both stitches from needle. There is a little demo of the RT stitch here(http://dixieredheaded.blogspot.com/2007/07/how-to-make-right-twist-stitch.html).
Some people also do the RT stitch by knitting the first two stitches together (do not remove from needle) and then knit the first stitch separately, slip both stitches off the needle. So there are two methods for the RT, I think the second method is supposed to be more prominent.