How can i hem a tie to be skinnier. And also is there a website that would teach things like tayloring suits?

prom is coming up and the only tie i have that matches my date is wayyy to fat. Also if there was a website that would teach a person how to alter or taylor a suit to better fit my body. this way i wouldnt have to pay a seamstress to do it for me. please any advice helps! :)