You will need:
(4) 1x2 @6'
(1) 1x2 @8'
(24) 1/2" dowels @21" ( they don't have to be 1/2" it's just what I used) that's 504" or 42' of dowels
Saw (any kind that cuts wood)
Wood glue (optional)
Screws ( I used 1 5/8)
Step 1: Drill
Take 2 of the 6 foot 1x2's and clamp them together and drill them with the drill bit that is the same size as your dowels. I started 4" from the top and then every 6 inches. Do the same with the second two 1x2's, but start 5" from the top and then every 6 inches. This will allow for your shoes to sit at an angle and not fall off every time you open the door.
Step 2: Install Dowels
Start sliding your dowels into the matching 1x2's. My dowels fit very tightly and needed some gentle persuasion with my hammer. This being the case, glue isn't really necessary. Plus this helps if you ever want to take it apart and move it with you. Glue is a more permanent option if you're having problems with your dowels falling out or sliding.
After you've inserted all your dowels then you can attach the two frames together. I simply did this with 6" pieces cut from the 8 foot 1x2 and some 1 5/8" screws. Always pre-drill a smaller hole as you don't want the wood splitting. This was probably not the best way of attaching the two as it looks as though the outward frame will eventually sag and cause me problems, however I kinda did this in a hurry as our previous (cheap plastic) over the door shoe rack had finally failed for the last time! No more amount of duct tape would hold it together.
(Side note- I built this in May and it's now of December and its held up quite well, although my son hasn't tried to climb it...yet!)
Step 3: Attach Brackets
I had salvaged the brackets from the previous cheap plastic one and was able to re-use them. However I have seem them at some hardware stores or here's a link from some that look like they will work from Amazon.
So here's where the last 1x2 comes into play. Cut it the same length as your dowels. I went with 21" as that's what fit best on my 28" door. After attaching this piece to your back frame attach your over the door brackets. I added a few 21" pieces lower down as well so the rack was sitting flush and not at an angle.
Hang your shoe rack and start putting all your shoes away!
Alternative options: if the over the door bracket doesn't fit for some reason you could always try a French cleat system. This would involve drilling into the door though and that may not be desired. However if you keep all your shoes in your garage as you enter the house the French cleat would work great as you can hang it on the garage wall and no one cares if you drill into that. :)