How's the best way to increase in your cast on row (row 1)?

What is the pattern? Are you needing to increase between sts or using existing sts?

cam

The pattern is st st. It's a bear, starting at the nose: cast on 6. Row 1 Increase in each st; 12 stiches.

Your best bet is kfb. (Vid in Increases if needed.)

cam

When a pattern says to inc in a stitch, it generally means kfb because the other increases are between sts.