When picking quilting designs, really anything goes. But there are a few things that can help you narrow down what you are going to do. Who is it for? Are there designs that might particularly appeal to them? How confident are you with your quilting? And how "uptight" are you? Will you be incredibly stressed if your quilting isn't perfect or can you look past some bobbles? If you're "uptight" (can't think of a better word right now), then you should stick with designs that you are very comfortable quilting; if you're more adventurous, push your limits (this is the best way to improve your quilting). Is there a quilting design that you want to master? If so, see if you can slip in small areas of this quilting design. If it's a new design, you might not want to fill the quilt with the design because you might get overwhelmed.
One of the best things that you can do is look at how other people have quilted their quilts. What appeals to you? What doesn't? What I like might not be what you like. Search for examples of finished quilts from the pattern that you used online. Search for similar patterns. The more examples you look at, the more ideas you will have.
Finally, my biggest advice for a new quilter is try to be the adventurous quilter and not the "uptight" quilter. While you are quilting, with your nose inches from the quilt, you'll see every mistake that you make. Other people looking at your quilt from a normal distance will not see your mistakes. And, as someone told me when I first started, the more quilting you add to the quilt, then more your mistakes will be hidden. So, if you don't like something, see if you can add some more quilting to hide the mistake rather than wasting your time removing your errant stitches. Generally, I only remove stitches if my tension was off or if my stitches were so big that they would catch on something. And always remember: HAVE FUN!!
