Remember, your overall GPA is not the only thing they look at. How well you do on classes that are important will give you more boost than say a 4.0 with easy classes. Therefore, I advice you not to take too many important classes together like what kimbanator said and just do your best. Also, as you take more classes in later years, your GPA is pretty much fixed at somewhere, so don't be too worried and let the stress affect your performance.