My advice is any pattern you love to make. But don't ask what their "colors" are or themes. I made that mistake once and ended up with a really weird color combination that they quickly grew out of and wanted another quilt. The best advice I have heard after that was to make a neutral color quilt. Many couples start with a king size bed which is a huge quilt. Think about a throw size. You will be glad you did. Young couples change styles often.