See also Notes on 18th Century Stockings

Knitting Gauge: 
__ stitches per inch, - 10% for stretch = __ st./in.
__ rows per inch

Circumference
A: Thigh: __ inches x __ st./in. = __ stitches
B. Lower thigh measurement (optional): __ inches x __ st./in. = __ stitches
C. Knee: __ inches x __ st./in. = __ stitches
D. Calf: __ inches x __ st./in. = __ stitches
E. Ankle: __ inches x __ st./in. = __ stitches

Length:
1-2: __ in. x r/in. = __ rows (__ decreases)
2-3: __ in. x r/in. = __ rows  (__ decreases)
3-4: __ in. x r/in. = __ rows  (__ increases)
Knit plain for one or two inches between 4 and 5.
5-6: __ in. x r/in. = __ rows  (__ decreases)
7: Heel flap = __ rows ( measure from bottom of heel to narrowest part of ankle -- usually three to four inches).
8-9: widest part of foot (where toes start) to end of toe: __ in. x r/in. = __ rows  (__ decreases)
9: Length of foot: __ in. (from toe to heel flap) x r/in. = __ total rows

Directions:
Cast on the required number of stitches, using either a larger needle than the size you'll be knitting with or two needles, to make sure that the first row isn't too tight. A two-strand cast-on is probably the most correct method (Rutt, p. 13).

Knit several rows of garter stitch (one row knit, one row purl).

Plain knit for __ rows from A to B and B to C, placing decreases in pairs on either side of your back 'seam' of purl stitches (see page on 18th c. stockings for options).  Space the decreases out evenly over the number of rows knitted. (Note: the pics are from a pair of 'trial socks' I've knitted; I'll replace them with pics of 18th c. stockings when those are available.)

Increase from C to D, again placing increases in pairs on either side of back 'seam'.  Space increases out evenly over number of rows knitted.

Knit plain for one or two inches below D.

Decrease from D to E.  Space decreases out evenly over number of rows knitted.

If you want to knit in purled clocks, figure out how many rows your clocks require, and start knitting them in before reaching point E.  To figure out how many rows to knit before starting clocks, subtract the number of rows required for the clocks pattern from the total number of rows knitted from D to E.

At Point E, divide the stocking into two parts.  The stitches for the front half of the stocking go on two separate needles; the stitches for the heel flap go on one needle. 

Knit the heel flap (knit, then purl back) to the desired length.

Divide the stitches for the heel flap evenly onto two needles. Fold the heel flap in half; bind off.

Pick up the stitches along the sides of the heel flap. Knit the gusset.

Knit the foot to point 8 (the widest point of the foot). Decrease to the end of the foot; bind off toe. 

Finished stocking foot, side and bottom view:

Also see:
Socks 101  
Socknitters.com lesson on knitting gussets