For future batches, it definitely helps to consult the style guidelines for the major attributes. If you are looking for a classic style taste, you want to be squarely in those ranges. eg an american pale ale should be in the 1.045-1.060 range and 30-45+ IBU. Compared to other pale ales, sierra nevada is pretty full and hoppy, so if you are trying for something like that, you shoot for the upper half of those ranges.
You don't always have to brew "to style", but it is a great starting point. eg you like a certain beer but wish it was a little more (whatever.) Or, you want to brew something that is between 2 styles. It really helps you get a feeling for what someone elses recipe might taste like and definitely helps if you are making your own recipes.