First of all, you have to measure your waistline. It is extremely important for you to take the right measurement. Otherwise you will not feel comfortable in your band. You have to note down the measurement from your hips rather than from the middle of your belly. The band should be comfortable and prevent the pants from falling down.
Then, you have to find an old tube or any other flexible cistern. Generally, the spandex shirt works best for making the band. You have to cut around four to six inches from the bottom of the shirt.
Now, take the scissors and cut the loop which is at the top of one of the creases of the shirt. After that, you have to take the measurement according to your waist. You should keep a room of around at least half an inch so as to accommodate the ridge.
Take a pin and place it on the fabric after folding it around 1/4-inch in order to secure it. Then, you have to sew it from the middle of the fold by the help of the sewing machine. After finishing, you have to fold it again and pin it as well.
Keeping in mind the first ridge, you have to sew the fabric again in the same line. After that, you have to line up the two corners together. To sew in a straight line, you can insert a pin in it.
After sewing, turn the fabric around in order to see your Bella band. Wear the band and check whether it is comfortable and helps to prevent the pants from falling or not.