craftgrrl | KNITTING - I need help with a pattern.

I was knitting up a swatch for the Turquoise Lace Sweater (pattern twenty-eight) in Rebecca issue 31, and came across a problem.

The lace pattern called for says that it is worked over 4 stitches, and following it says:

Row/round 1: yarn-over, 1 slip dec (=slip 1 knitwise, K1, pass slipped st. over); K2 tog, yarn-over.

And this is what I did: I did a standard yarn over, passed the extra stitch onto the other needle, knitted one, passed the extra stitch over to make it a slip-stitch decrease, and then I did the K2tog and another yarn-over after the K2tog. It seems to be taking up more stitches than it should. Am I doing something wrong? Because I knitted a couple of rows following the lace pattern exactly as the way it says for rows/rounds 1 and 2 (2 is basically a straight knit or purl row) and it didn't even come close as how it is seen in the modeled picture.

Please help me if you can. And I am able to provide more info. if necessary.

P.S.
This is also my first time working with yarn-overs.