The best way to create a sigil is to make your own sigil, however tracing a sigil created by someone else will not change the fact that it is someone else’s work. The important part is that you feel that the symbols or words have power to you.
When you use a sigil created by someone else you’re using a random symbol of someone else’s creation to focus your magical intention. This can still work and be effective but it is not tapping into your mind and your magic in the way a sigil is supposed to work.
Mastering the art of how to make a sigil properly comes with experience. I like working with paper and a pencil that way you can easily make corrections or changes, however you can experiment with other methods. Digital art, paints, collage, ink pens, can all make excellent sigil mediums.