Many of the food items represent prosperity, good fortune and health. (Unfortunately, regardless of how much osechi I've eaten I haven't seemed to have gotten any smarter, richer, or more industrious.) The basic components are the same, but regional differences are reflected in the sweetness or saltiness of the flavoring and the use of local ingredients.
One thing to keep in mind when looking at osechi is that presentation is very important. You may notice a pleasing balance of colors. What may be harder to notice, though, is the efficiency with which each layer is packed. The more elaborate osechi will have vegetables arranged in ornate designs, representing seasonal shapes such as pine cones and plum flowers.
The section below describes some typical osechi food items, and explains what they represent.