Mitered square cardigan help

I am starting a mitered square cardigan in the book Skein For Skein
by Cheryl Potter. Anyway this is the mitered square instructions:
,Basic square for the body:
With first yarn, cast on 87 stitches. this includes i st at sides for selvages. Purl one row,(WS) this is not part of the square pattern.Row 1 (RS)sl1kw-K2tog-psso. Row 2 Purl.Row 3 K41 sl 1 kwK2tog-psso, knit to end.

Work in est pattern,decrease 2 st EOR until 21 remain.End with Row 2 Now dec every row working de on right side as above wrong side as follows sl3 st kw one st at a time to RH needle,sl3 sts back to LH needle and P3 tog tbl until 3 st remain. I understand the directions but I am still windng up with the same amount of stitches. Am I doing this wrong? Should I be doing a right and a left dec stitch on each side of the mitered center? Also my edges are wavy.:wall:

The sl1, k2tg, psso is a double decrease which takes 2 sts away every RS row. That dec is in the middle of the row, so R1 should be k42, dec, k42. R3 is k41, dec, k41. You knit 1 less st before and after the dec every RS row.

If the stitch number is not changing, then you must be adding a stitch every row. Look at the sticky thread here and make sure you’re not knitting 2 sts into the first st of each row.

thank you for posting a reply so quickly . I am going to try again. I did not realize to watch the st after the st carefully. I think I just get excited and go like a house on fire and want to stay up all night. I found I have a tendency to not be careful and my knit st when wrapped around the back becames an extra st. I just learned to left hand knit a few weeks ago. That helps my tension issues, combining this with the be extra caeful I may just lick this problem. Thanks again