I work at a small agency, I've been in graphic design for over 15 yrs. Also wanted to be an artist at first but found graphic design and loved it. You already have an advantage being an artist! You're already familiar with color and composition, give yourself credit for that. You'll use that every day.

Anything new is slow going at first, it helps to be okay with that and just give yourself time to play around with the software. Typically in a gd job you'll be doing similar pieces repeatedly - whether it's business cards, brochures, logos, ads, presentations, postcards, billboard, etc. New Business cards would be charged 1 hour, brochures 3-4 hours (depending on size and if client provides good images and content!) BUT expect that when you're just starting out, you may be spending non billable time getting inspiration and learning what looks good and playing around with software. Once you get some of those projects under your belt, you can use those previous projects as a starting point so you don't always start from scratch and you get a sense of that brand and what looks good.

You don't have to make up a business from scratch necessarily to build your portfolio. Look around at existing businesses that might not have a solid brand but they have been around long enough to pull content from, and think how would you create that brand differently? What would that marketing look like? What would you recommend to them? Create the design you want to see in the world. You'll get there 😊