There seems to be some variation in the fit of the projects on Ravelry (free to join), too.
Be sure you're getting the gauge called for in the pattern. You might also try blocking the hat (unless it's acrylic yarn) into a more tam-like shape.
One reason for the ssk (sts slipped knitwise) and improved ssk (one st slipped k-wise, the second p-wise) is to give a nice flat decrease. You can look up videos for both on the Glossary page if you'd like. This hat in particular has very pretty decreases across the top.