The Yarn Over increase (YO inc) is used predominantly for laces and the direction in which the yarn is wrapped depends on the preceding stitch (K or P) and the subsequent stitch (K or P). For the YO inc after a K stitch and before a K stitch, the yarn is brought under the right hand needle and wound back to front over the right hand needle to be in the proper position for the subsequent knit stitch. This is one of two YO increases used in the Basic Toe Up Sock - Short Rows Toe. For additional instructions and photos read more...
Steps
It is not as difficult to remember all the combinations as it may at first appear; if you yarn over for the increase in the wrong direction, the yarn slips off as soon as you pick up yarn for the next stitch because you "unwind" the yarn. So, picture the direction the yarn will be drawn for the stitch following the increase and where the yarn needs to be for the subsequent stitch (front or back) to wrap the yarn correctly. This way you won't have to remember combinations.