It may seem that 95% of all the water soaking your pants and shoes got shot up at you by your tires; fenders solve that problem. If you have eyelets on your dropouts you can bolt on some nice Esge or Zefal fenders in 15 minutes and leave them there. Your bike will stay cleaner in dry weather too and you will look real cool. If you don't have eyelets you can snap on Zefal mudguards, which are half-size fenderettes or fenders for people who don't want fenders. They will do most of the work. To block some of the low spray that will still come off the front tire you can zip-tie, velcro or tape on a cut open plastic milk jug to your downtube. A slicker solution is the Zefal Croozer, which does exactly this, but looks like you couldn't solve your problem without throwing money at it.
Keeping your upper body dry is another problem. A rain jacket alone won't do the trick for keeping your shoulders, chest, and upper thighs dry. There are rain suits, but frankly I donŐt like them; they are cumbersome, expensive, and hot. My solution is to whip on my cycling cape and brave the elements.
Capes aren't easy to find but here are two sources: Rivendell supplies a beautiful, durable, waxed cotton model from Carradice in England. It is perfect and, I think, will last forever. The second is Loghouse Designs' coated nylon cape. You can keep your head dry by putting the hood of the cape between your head and helmet. If you donŐt have a hood, you can put a shower cap over your helmet.
In all but the heaviest downpours I have gotten along okay without soaking my shoes or lower legs but you can find or make booties and chaps if you need to. I usually ride without gloves, but when it's cold and wet you will want Neoprene, Gortex or dense wool gloves. They will keep you warm when wet.
These are a problem. I'm only semi-blind and take my glasses off when it's wet. Contacts work great in the rain. You people with perfect vision are blessed and should be thankful.
Wrap all your gear in plastic bags and put them in your panniers or bags. Don't have bags? Your local bike shop will probably have different types of bags to choose from.
Turn on your lights and ride smoothly. When riding in the rain squeeze your brakes lightly for a few seconds before applying them hard--this squeegees off the water from the rims and improves the brake traction enormously. Rely more on your rear brake in the wet. If your front wheel locks and skids you will go down.
Once you are prepared for rain you will look forward to every opportunity you get to ride in the wet. You will look groovy and proud.
Children will admire you and motorists will think you are out of your mind. You will glide through the streets of your city with peaceful, poetic and beatific thoughts. People of the opposite sex will rush up to you while you are locking your bike. They will assume you are French and embarrass themselves trying to speak in your supposed native tongue. Your life is going to get much more interesting this winter.