A dozen or so row before the heel placement, on the INSTEP side of the sock, begin adding stitches. 4 to 6 stitches at either edge (I place mine 1 stitch in from edge)--Increase 1 stitch (each side of the instep) every other row.
I use a lifted increase (easy-peasy on right side, no so much fun on left side) since I think this is one of the easiest tightest (no holes) increases.
If, (as in these socks) I complete my increases before I reach the right row for the heel, I just continue (in this case, 2 rows) knitting with no increases or decreases.
After working a row of waste yarn for the heel, I start decreasing, reversing the pattern and decreasing 1 stitch (each edge) until I am once again at the correct number of stitches.
Knitting 8 stitches to the inch, 2 sets of 4 stitch increase yields an extra inch of ease at the widest point of the heel.. and for me, make the difference between socks that fit, and socks that almost fit, (and are a pain to put on and take off).
I need to give a big thanks to Janis (aka Knit*Therapy), this sock yarn got me going.. (I haven't knit a pair of socks in 6 months!) I love how the finished sock looks, and can't wait for the fall to wear them!
The last skein of yarn has been dyed, too--for now. I'll need to get some more white wool and more dye stuff before I can continue. This skein is a bit lighter than I wanted—but still a nice cream-cicle orange. I'll keep it as is—and work for a darker orange at some point in the future.