Unlike a lot of other office-oriented work, graphic design work requires more to qualify for it than a college degree, relevant experience and a CV. A portfolio is of utmost importance. It should include all examples of work (or just the best of it, if you’ve been in the field for a long time and have built up a large backlog) that you’ve done in the past for clients, sketches of ideas and pretty much anything that’s related to the creative process that you’re proud of.
Of course, the other aspects of being job-ready in this field should by no means be ignored. If you’re stuck in the classic catch 22 of not being able to get a job because you have no experience, and not being able to get experience because you don’t have a job, then you can try to intern for nearly any relevant company, and you can also supplement this by doing freelance (contract) work for the same entities. College isn’t as important as having past experience from what I can gather from browsing job listings on websites such as Jobs.ie or Indeed, but pursuing one never hurts. Ballyfermot College Of Further Education, for example, does a QQI Level 6 that covers the basics of graphic design, in both theory and practice.