The point is you want to already have at least a mid looking portfolio when switching from a full time job to a freelance career. Ask your company if they are ok with you posting work that you are doing inhouse into your portfolio, this way you don’t have to work on self-initiated projects and it’s a win-win situation for both you and your future freelance career.
As you do this you will notice that your work will start to get attention and you will receive emails and inquiries. Some of them will come from people who really are in need of a solution to their problem and some of them might disappoint you because the message will be “I need logo”.
Try to notice which of the platforms you are uploading on, brings you the most exposure and focus on that one. In my case Behance and Dribbble work best. I’ve had some very good clients from Behance, who still give me work to these days. But for me personally Dribbble has been the best tool for client work and the most rewarding financially.
Some other great tools to get clients are of course — personal website (with good SEO) or content that will bring traffic to it. Youtube is also a great platform to post videos of you teaching people, however you might want to think about what kind of videos you would like to post, in order to appeal to a not to general audience.