Dear Rachel,
When you make a hat, the brim must be clipped every 1/2 inch around the inside edge in order for it to (1) fit your head and (2) to fit onto the side crown.
If you use the Wild Things pattern, I have used it, and the brim is not what I would call a sunshade brim. However, you can make your own brim. Trace the inside crown seamline (not cut edge). Make sure to trace the half pattern in the middle of a big piece of paper, and then flip it and trace the other half to make a whole oval. Mark center front and center back. Now, measure out on your paper the width you want your brim. Measure and draw a line all the way around the oval. At the center back, slash the brim, and cut it out. Now, divide the brim in about four or five equal parts, and slash the brim along these lines. (Make sure that the CB is marked; all lines will look the same once slashed. Now overlap 1/8 inch the outer edge of each slash and tape closed. Now try on the brim, and see if it's what you want. You can make it wider, put more slashes in it to give it more shape, or make it smaller by just cutting the outer edge. The back won't meet now, and will need a seam. When you're satisfied with the look, trace the result on another piece of paper and add seam allowances.
Teri