WOOD
I typically opt for a 1/2" to 3/4" piece of plywood or particle board. Depending on what you buy and the thickness, a 4' x 8' sheet of this will typically run you $15 - $18. As luck would have it, my husband was having some other wood cut at Home Depot (where I recommend you buy this since they'll do some cuts for you for free) and found a piece that would work in their "scrap" pile. The piece was marked to $2 but since my hubby was making friends with the guy there, he got it for $0.50. Say what? Awesome.
BATTING
Depending on the shape and thickness of the headboard you're doing, quilt batting or foam will work to provide thickness and cushion. In this case, I decided to purchase three yards of solid comforter fill (i.e. what you'd put in a comforter if you made your own). It was one piece and worked with a 40% off a single by the yard item coupon at JoAnns Fabrics. Total here: $9.00 (big score ... I've paid over $20 for foam or batting in the past).
FABRIC
I always start in the clearance fabric section first, because ... well, why not? You never know what they'll have and some fabrics can be very pricey ($35+ per yard). I found a solid purple fabric here that was on clearance for $5 a yard. Also, since it was the end of the bolt, I got an extra 50% off: total, $5.50 for two yards.
Total cost of headboard: $15.00
To get started, I measured the width of the bed and then put a piece of tape on the wall to represent the height of the headboard; then I measured that. It would be 42" W x 40" H. Then I got out some wrapping paper, yes ... wrapping paper as in presents ... and I used that to make a template. I cut a piece that was 21" wide (1/2 the width of the headboard).
I doodled out the shape I wanted and then put the measurements on their for my handsome carpenter to reference. Then I drew out what would be half the shape of the headboard. You might be able to tell from some of the lines that I didn't like my first attempt. As long as you can remember which line you actually want when you cut it, really doesn't matter how many scribbles you have.
So then I cut out my template and taped it to the plywood which by this point was exactly the height and width I needed. (Again, Home Depot can do this for you.) I traced out one side on the wood, then flipped it over, taped in place, and traced that side too. See?
Then all that was left was the cutting. Well at least for this portion.
When it was ready, I laid the ironed fabric down on the floor with the side you'll see on the bed facing down, and laid the fluffy stuff on top, followed by the wood. Then it's time to staple. I use a small handheld version (non-electric) which works well for me. It's a T50 if that means anything to anyone. (Note I only know this because I had to phone a friend from Ace Hardware this morning when I couldn't figure out what size staples I needed.)
Once it's laid out, I make sure everything is tight and then I start by stapling the bottom first. It's important for the bottom to be straight and secure.
Once the entire bottom was stabled I tighten the fabric again (as you'll do throughout the process) and stapled at the top. This allows me to keep the fabric straight and make sure it's tight without looking lumpy or out of sorts. Then I gave the batting a little trim (see upper left of pic below), followed by the right (not shown here). Afterwards, I stapled to the sides ... doing some on the left, then the same amount on the right, alternating to ensure things remain even.
Throughout the process, I'll pick up the entire headboard and lean it against the wall (front facing me) making sure everything looks right. The last thing you want to do is finish without having checked your work, only to find things are crooked or bunching in all the wrong places. It's like having a headboard wedgie and that's never good.
When I get to the curved parts, I have to pull and push and tug and staple closely. In some cases, I needed to cut the fabric to release some of the tension and get it to pull correctly in the curves. When doing so, you have to be careful not to cut too close to the edge/front, or the whole thing could be ruined (been there done that, there were tears).
Alright, so when all is said and done, my headboard looked like this.
And here's the finished room. It's not perfect, but given I was trying to salvage some of what we had (including the drapes which are staying for a while yet), it's a pretty big change. Most importantly, my little London is very happy!
BEFORE (post crib, just brought in bed):
AFTER: