Both GIMP and Photoshop can be daunting for the new beginner. I'd suggest reading as many tutorials as you can find... there's loads available on the net. Or better yet, draw out a draft copy on paper before firing up the program, and then check the Help or on websites to help you achieve what you're going for. For example, if you wanted to make a rounded logo with burnished copper-effect trim, and a banner for the title, you'd look at making a circle, how to add the trim (easy with a gradient filled stroke), then adding a banner, and finally adding text.
Once you're used to working with the program, it becomes a snap. But there's been many a time I've given up on an idea because I simply didn't know how to create the effect I envisioned in my head. This will come with time, but perseverance and a desire for knowledge will get you far.
That said, a healthy dose of creativity goes a long way too...
To sum up: Read shoitloads of stuff, and learn the basics first. You'll be on your way in no time.