I haven't looked at much as to how to do a sigil. What I like to do is write what I want to manifest on a piece of paper. Then cross out ever other letter and make a symbol out of the remaining letters. At that point I've taken an idea and made it a tangible thing on paper. Then I go outside and burn it. The ashes fall to the earth and the smoke rises to the sky and my idea becomes part of the everything. Anything that doesn't burn away is meant to be kept on a human level. This one just turned out more beautiful than most.
I don't claim to know how to do magic but I feel like if it makes you feel something then that's what you should do.