Dust mitts are easy to make. I created my pattern freehand drawing about an inch to an inch and a half out around my hand. You could use an oven mitt to create the pattern or find a pattern for an oven mitt online--there are several such as this one at Skip To My Lou. (Remember that an oven mitt will be thicker. You don't want to make the dust mitt that big. It might help to throw one together using scrap fabric to get an idea of how big you want to make it.)
I folded each square of fabric in half, pinned on the pattern and cut out the two pieces. Here's a picture while I was in the midst of cutting.
If you place the cuff end of the pattern at the bottom finished edge of the cloth, you won't need to do any hemming there. I decided against serging because getting around the thumb would be a pain. Instead, I sewed a scant quarter inch seam around, turned it right side out, and top stitched a quarter inch in to enclose the seam.
This fabric doesn't have a right/wrong side. If yours does, you would start this with the right sides together. In the photo below, you can see the scant quarter inch seam before turning right side out. Be sure to reinforce the ends with back stitching at each cuff end.
(Remember to reinforce the start and stop points at the cuff when top stitching, too.)
Dusting with two of these on really is much faster. When the front gets dirty, just switch hands and use the back. You can even turn them inside out to use the other sides. It's so much easier to do lamps, vases, frames, and dining/kitchen chairs. Microfiber material holds an amazing amount of dust.
These make great little gifts for those setting up housekeeping. Also, consider making smaller versions for the kids. Mine loved the novelty of two-handed dusting with the mitts and finishing the chore quicker when they were young.