A trend that I tend to see in magazine ads instead of three dimensionally is the prep look that is, a pair of dress shorts, a nice shirt (and tie), and a sport coat. First off, have you worn this? If not, would you wear this?
Rules: Your shorts need to be extremely well-fitting. That means, possibly tailored, possibly cuffed, definitely above the knee, no bagginess to them, no cargo pockets, and the appropriate contrasting color in comparison to the jacket. If you are going to wear a matching colored short to jacket combo, you may want to buy them together so they are more like a suit than anything else.