Welcome to the Guild, Jake! I would say, if you're at a loss as to how to begin, start out with one of the tutorials. You don't have to create a masterpiece right off the bat; sometimes it's good just to screw around with the tutorials and software and see where you go.
Are you using Photoshop? The GIMP? There are tutorials geared towards each, and tons more for other software as well. What's your ultimate goal with your map - do you want it to be a realistic atlas-style map? An antique hand-drawn one? Something else?
The first bit of advice I can give you, just based on what you've posted, is that it's generally not a great idea to fall into the trap of 'fill every square inch of canvas' - your map will look more natural if you don't try and fill every corner with landmasses as you've done here. Space things out a bit, make it look more random.