I recommend using Photoshop if you're in the Dark side where we have cookies and stuff. Pretty decent for a 3rd signature ever made. Try to learn the fundamentals like the rule of thirds and indulge yourself in the many styles of "signature"-making. I know that you will get better and better as long as you get inspired and "annex" the styles of other people and re-make them into your own style.
[ Hi! My name is TheShinukage and I approve this message! (Promise me to thank me for it too!) ]