I teach a Learn to Quilt series at my LQS, and I suggest to new quilters that they use the dye swatches on the selvage of their focus fabric to help select colors. Another thing to try is buying from the same collection as your focus fabric, and/or using jelly rolls, layer cakes, FQ bundles, etc. When I was a new quilter I tried to buy from the same collection, but over time I have come to feel that buying only from that collection can be, for me, a little limiting. I prefer to select a variety of other fabrics that mix in well to prevent my quilt from looking like a kit from a fabric company.