I redid my sweater boots to a covered pair of shoes. I previously used an old pair of sandals, which were not tight enough and water leaked in when it rained or the ground was wet. The shoes I used were flexible, because you will need to bend the shoes slightly to fit the finished sleeves right side out and I will explain in the end of this tutorial.
First, cut the sleeves off the sweater of your choice (I bought mine at the thrift store for approximately $2.) However, I recommend a darker color, so it will not get dirty easily. Second, turn the sweater sleeves inside out, with the shoulder side of the sleeve to go on the front of the shoes and the armpit side of the sleeves will align on the heel side of the shoes like this: