A great addition to a great series!
Once you decide it's time to get started with your city, you may find the early going to be very familiar if you've played any of the previous Sim City games. You'll start by plopping down a power plant, preferably one that doesn't create too much pollution, and then laying down some residential, industrial, and commercial zones, then giving them some time to incubate. Laying out zones is as easy as dragging rectangles using your mouse, but Sim City 4 tries to make things even easier on you by automatically inserting streets, giving larger zones a grid like pattern. This is a mixed blessing, since these auto-built streets often don't line up as you try to construct adjacent zones, leaving your city with bits of wasted space here and there, at least until you get used to dealing with this feature. And since city maps in Sim City 4 are smaller overall than in previous Sim City games--probably a necessary limitation due to the fine level of detail you'll see down to individual houses and sims--that wasted space could be a big missed opportunity for your city. Plus all the extra roads can really hose your budget early on. The auto-roads feature really should have been optional.
You'll have to start small, but think big. As in Sim City 3000, the three zone types each have several different density options, so light-density residential zones are likely to sprout small houses or low-income apartments, while high-density residential zones could turn into tall, fancy condominiums. Denser zones are costlier to put in place but pack in more people, which means more tax dollars. But in Sim City 4, it pays to start slow. The early going can be very challenging at first (and there are no difficulty options available to ameliorate this), as you'll naturally wish to immediately add all the amenities you'd want in a city: running water, schools, hospitals, police stations, or a football field. At any rate, a fledgling town needs only the basics, and a continuously updating news ticker that's part of the interface will keep you informed about whether your sim population needs anything you're not already providing. You'll eventually get a feel for how to get people coming into your town without driving your budget too far into the red. The goal, of course, is to make your newly established city profitable as soon as possible, since that's when you can start expanding in earnest and finally afford that hospital or police station you've always wanted next to your football field.
Having to contend with the constantly shifting demand for the three zone types while continuously adding better services and transportation options for your population and while also keeping an eagle eye on your monthly budget adds up to some involving game play. Sim City 4, like its predecessors, succeeds at being an active, hands-on game where there's usually something interesting you can be doing. Even if you're waiting to rake in a certain amount of funds, you can use that time as an opportunity to scrutinize the many different statistics and charts available to you or to correspond with your various advisers on how to proceed. Or you can use the handy query tool to click around your city, gleaning all kinds of information, including a few amusingly pointless statistics. You can even just sit back and observe your city at the closest zoom level. See those crime-scene-style chalk outlines near your football field? Those mean you probably should spring for a new police station thereabouts. All this is not to say Sim City 4 is a fast-paced game, because you can play it at the rate you want. It's possible to pause the action outright and build as much as necessary before starting the clock back up, and you can freely switch between three different game-speed settings.