hopefully this ends up making sense!
the bonnet i made first when i took the pics has a separate brim for contrast when the brim isn't folded back. the sugar skull bonnet is simpler and the brim is part of the body of the bonnet, and only has contrasting fabric on the outside if you fold back the brim.
the instruction will be for the bonnet with the separate brim, because that's what i have pics for, and my camera went missing in the move to our new house!
i'll include measurements, cause some people like them, but if you measure the size you need on your baby it'll be easier. (assuming a baby is on hand, or it may be more difficult...)
you need 2 different fabrics for contrast/because it's reversible, and interfacing for a little stiffness. i used fusible, but you could use sew in, it wouldn't matter.
to make the rectangle for the body of the bonnet i held up a piece of fabric from under one ear, over her forehead, and under the other ear, where the front of the bonnet goes. i later decided for the sugar skulls bonnet that it should go from jawline to jawline. whichever you prefer!
that plus seam allowance is the width from ear to ear, of the bonnet body. for the length i approximated how far back it needed to go by holding it up to amma's head again.
the rectangle measures about 13" wide and 6 " long. (my daughter is 7 months old.)
cut one from both fabrics, and 1 from interfacing.
for the brim make it the same width as the body, and 1 and 1/2" deep. i cut it as a long skinny rectangle, folded it in half, and rounded the edges by cutting both together so they'd be symmetrical.
cut one from both fabrics, and 1 from interfacing.
the finished ties are 2" wide. one is reversible, and the other bonnet has one solid piece for both sides. cut 2 that are 2" wide and add seam allowance, or cut 2 that are 4" wide plus seam allowance, depending on if you want reversible ties. (not that you really reverse them, but you can tie the bow so the outer fabric contrasts with or matches the outside of the bonnet.)
they have no interfacing.
make the ties first, because they need to be finished to sew the bonnet together.
sew the tie sides together, with fabric right sides together. sew one edge shut, turn it right side out, and don't worry about closing the open end. it'll be sewn into the bonnet seam when you attach it.
the tie that holds the back is 1 and 1/4" wide. for contrasting sides, cut it 1 and 1/4 plus seam allowance from each fabric. cut it 2 and 1/2 inches wide plus seam allowance if only using one fabric.
also no interfacing. sew the tie side seams, right sides of fabric together. sew one end shut. the open end allows you to turn it right side out. do this, then topstitch it closed after folding the raw edge in. (iron the fold down before sewing if it floats your boat.) if you want them to match perfectly, topstitch the other end that's already closed.
now you have this- (the rectangles are stacked and you can't tell, but there's 2 contrasting fabrics, and one interfacing)

for the sewing part, i took no pictures... and you may find a better way to construct it, i don't make reversible stuff very often. or never used to...
iron your interfacing onto your rectangle and brim piece. sew the rectangle for the body to the contrasting brim piece, right sides together. do this once with your inner and once with your outer layer.
place these 2 pieces you sewed together (the body of your bonnet) right sides together. place the 2 ties for under the chin inside the bonnet with the edge barely sticking into your seam allowance right next to the brim. if you didn't make a separate brim, place the ties behind the fold line for your brim (like on the sugar skull bonnet). pin if you need to.
now you'll sew the body together. in the back where the tie gathers the back, you won't sew all the way back. start stitching 1 and 1/2" away from the back edge of the fabric, to leave room where the ties will run through the fabric.
sew from 1 and 1/2" away from the back edge all the way around the bonnet, to one and 1/2" from the back edge on the other side.
(if sewing instructions are clear as mud, let me know and i'll take pictures...)
now take the 1 and 1/2" raw edges of the back side seams and hem them, serge it, stitch it down in some way so it's not a raw edge. separately. (don't sew them together like the seam, or where will your ties go?)as i make more i'll probably figure out the best way to do this...
turn your bonnet right side out.
iron down the back seam allowance and stitch the 2 sides together to close up the bonnet, so the raw edge is inside the bonnet. it'll look like top stitching, except there's no inner seam. the ironing may be easier before sewing the 2 sides of the bonnet together.
now your bonnet should be all sewed together, with a hole on each side of the back to thread the ties through. thread your ties through. attach a safety pin to push it through if needed, i got my finger in the hole...
then scrunch the tie toward the back top-stitched seam so you don't sew through it, and sew a parallel line across the bonnet to create a channel for the tie, about an inch away from the back seam. (you could create the channel for the tie first and then thread it through, if you are afraid you'll sew through the tie) i found it faster to do it without making the channel 1st...i'm the type that won't stop to pin something unless it's slippery as ice...
gather the back with the tie and now you have a bonnet! iron the brim back if you want to, i did with the sugar skull bonnet because i like her face exposed more, and i know when she wore the brim forward i couldn't see her face a lot of the time....
there are probably better ways to construct it, i haven't done much reversible sewing... and suggestions are welcome! i also have a baby in my lap who doesn't want me to type this, so sorry if it's not clear enough. and most of my pics seemed irrelevant, should have taken them of the sewing. i think my camera died that day...
this is the bonnet from these instructions-



this bonnet has the simpler brim thats built into the body, and the single fabric ties, so less sewing.