How can I make this image a higher quality? It looks like a low quality image right now and I can't seem to figure how to fix that. I use Photoshop for my editing, but suggestions on other platforms would be appreciated too.
Take a black ink pen that gives a lot of ink and write the signature several times on white paper.
Select the best signature and take a pic with your phone or digital camera, well lit, from within 1 foot.
Open it in photoshop and adjust levels or isolate color channels until you get one that looks very contrasty and crisp. Use this to mask out the signature.
Save as your favorite file type.
Like Scott said, I wouldn't try and improve it any further, the current one looks legitimate and that legitimate look is very professional (in my opinion) compared to those digital ones that look like (and I've seen that some actually are..) a typed cursive font.
The image trace feature in Adobe Illustrator could also help, it works best with basic stroke & outline images.