I like to learn about the person receiving the quilt. This helps in choosing a design that will compliment them and what they enjoy.
I also look at the fabric patterns to see what they are doing. Are there swirls, points, shapes, vines, etc. This is a huge clue in what quilting patterns will work together and compliment the quilt.
Choice of thread colors can very greatly. To blend or not to blend, that is the question. Most of the time the thread will blend right in and all you will see is the classic quilting lumpy effect which makes the quilts feel so good.