Siscast is a useful tool for figuring out how you want your schedule to look next quarter. Go to the website, put in the classes you want to take along with any time restrictions (e.g. no class after 9PM) for your schedule, and it will give you all the possible schedule combinations. Just don't spend too much time on it detailing your perfect schedule because once you actually get to registration time, you may find that some of your preferred times are already filled.