Those who appeared here said the gist of it.... You MUST have a degree of knowledge in this field and a portfolio.
At your stage, you are presently gathering data and accumulating knowledge. Do not forget this is a broad spectrum... this includes product production phase - printing, materials. newspaper advertising, etc. Your artwork may be dependent on these elements. It's not a matter of "Create the artwork, print on this paper at this size, deliver to client". You must have knowledge in the production phase caz it may save you time or save money for you and the client in terms of steps to take to create the work.
If you want to start this, you have to meet people. This means you should be armed with a PORTFOLIO. Even right now you can achieve both... talk to friends and relatives.... they may need some design work - posters, business cards, Greeting cards (printed and digital media) , personal stationary, etc... . Include whatever you designed for them in your portfolio - "Poster Designed for Mr /Ms" .... so on so forth. And from your friends and relatives , ask for referrals .
If you feel comfortable, visit the businesses in your area. They may need a brochure or newspapar ad.