Hi Cressida, welcome to the forum.
I notice you're from Colorado Springs. A good deal of my family lives up there (parents, grandmother, aunt & uncle & their kids). Are you studying graphic design in the 'Springs?
My advice on marketing one's work: develop a strong portfolio and keep updating it with improved work. Formal study in art schools and other programs can help you develop more focus on the portfolio. In marketing for a good job with a major
sign company or environmental design firm your portfolio will need to demonstrate a strong and sophisticated sense of graphic design and typography.
You can take the portfolio and show in a number of different manners. High quality printed "tearsheets" (in postcard, rolodex or other formats) is a traditional method that still works. Doesn't hurt to have your own website either.