Choose a thin needle and start with 16 needle. When there is one needle left at the far left of each row, add another group of needles until the size of the upper is suitable for the width of the shoes you usually wear, and then stop adding needles.

After the vamp reaches the instep length, close the needle on the side not close to the sole until three needles remain at last; Then sew the flannel inside the vamp, punch out a sole with a flat needle, and finally sew the vamp, sole and insole together.

Select fine needle, starting with the first row of 16 needles, and gradually adding needles later. Then according to the traditional knitting method, make two rows at a time, and add a group of needles when there is one needle left in the leftmost side of each row.

Compile in turn until the size of the upper is suitable for the width of the shoes you usually wear, and then stop adding needles. The vamp grows to the back of the foot and begins to weave the "ears" of the shoes, leaving some stitches in the middle, and the remaining stitches are evenly given to the left and right "ears".

When knitting ears, don't take in stitches on the side near the sole, and take in stitches on the other side every time you finish knitting until there are three stitches left. Then choose flannel, sew it in the upper, and then use flat needles as soles. The size can be slightly smaller than the bought soles.

Sew the insole and sole together with crochet, and then sew the upper and sole. In order to keep warm better, you can also sew a layer of flannel on the woven insole before sewing the sole, so that the warmth of wool slippers will be better.