WOVEN... You should use woven fabric for bias tape.

FIRST... I use approximately one yard of broadcloth and open it up so it is a single layer. Grab one corner and fold it over to the opposite selvage edge so your fabric is now folded in a triangle shape. Square it off as best you can along the selvage edge. (The selvage edge is the side that is "self-finished", not cut by scissors.)

NOW... the diagonal folded side of your fabric ought to be a near perfect bias. Flatten the fold (or iron it) and then cut along the entire diagonal fold. Leave the fabric folded double, don't separate the two pieces.

NEXT... Use a yardstick and a sharp #3 pencil to lightly draw a long line one inch from the bias edge that you just cut. Then draw another line one inch from that. If you want your Bias tape to be wider, then space the lines more than 1 inch apart. Continue drawing straight lines, spaced evenly. Each line will be a bit shorter as you work into the corner.

CUT... along each one of those pencil lines. When you are finished, you will have LOTS of bias strips.

LONGER LENGTHS... If you need some really long lengths of bias tape for your project, then you will need to piece some of your strips together to make the desired length.

IRON... To prepare your bias strips for sewing, you must iron them. Fold each raw side of the bias strips in toward the center, pressing as you go. Leave a little gap at the center. I use a steam iron for best results.

After both sides are pressed flat, then fold the piece in half and iron it again. Now you have your own Bias tape, ready to use.