Knitting lace patterns

Help please!:pray:
I have been trying to knit through a couple lace patterns, but keep running into problems. The main problem is that I always seem to have too many or too few stitches. For example, I’m told to cast on 25, but what I go through the first row’s instructions you would actually need 36 stitches. Later in the pattern I work my way through the instructions and had several stitches left. I have knitted complex patterns before but have never had this much trouble, and it has happened in two different patterns I have attempted in the last week; I cast on, work a couple rows, see that things are not working right and take it off and start all over. What am I doing wrong?!? This is one of the patterns:
http://knitty.com/ISSUEspring05/PATTbranchingout.html

IN alot of lace pattrns the number of stitches are variable. IN the exapmple above:

caast on is 25 stitches. Row one is:

Row 1 [RS]: k3, ssk, yo, k5, [yo, k1] 5 times, yo, k5, yo, k2tog, k3 (

which USES 25 stitches but creates 31 stitches.

Make sure you’re not knitting an extra stitch for the YO. You only wrap the yarn around the needle for a yarnover, not wrap and knit a stitch, then knit the next st.