The thing I look for consistently when I'm shopping for a new piece is a quirky detail.  I love it when a collar or stitching is unique.  It makes even inexpensive pieces feel special.  It also makes things stand out from a trend.  Unique details are much more eye-catching and comment worthy then trends.  But even if you are going for a trend piece, try to find one that is different from what everyone else will have.  I remember being in high school and always being drawn to this concept.  Then at school everyone would have the same shirt, and mine would be different, and I would feel like I was odd man out.  It took me a long time to realize that I had a unique eye, and the ability to capture a trend and make it your own is a good thing.