I need a little help...

This is going to sound a little odd, so please bear with me.

I'm scared to sew together my fursuit heads, thinking I'll mess up and it'll be too small/backwards/whatever. >>

Does anybody sew up their heads, and if you do, how? I know you make a pattern and sew all the pieces together, but do you leave a 1/2" seam? <: Thank you!