I have two ironing boards that I did this to and love them now. What they came with was too thin.
We had some carpeting laid in a few rooms and I saved the padding that was left over. Took it and cut it out to the size and shape of the ironing board. Laid it on top of the board and then covered it with flannel. Then made a cover out of cute fabric and stretched it over the two layers and gathered underneath with the drawstring I put around the cover. Looks great and nice and padded. Cheap and you don't waste any batting!