For the most part, Vancouver central sits on a peninsula, which makes it compact and easy to explore on foot, especially since most streets are laid out on a grid system. To get your bearings, use the mountains as your "true north" and you can't go too far wrong. All the avenues, which are numbered, have east and west designations; the higher the number, the further away from the inlet you are.
As with most cities, a car is a liability: streets are congested and parking is expensive. Central Vancouver is quite walkable, the transit system -- a mix of bus, ferry, and the SkyTrain, a fully automated rail system -- is easy and efficient to use. Just be sure to travel with correct change. Taxis are a relatively inexpensive option, too, if your feet are tired -- though somewhat harder to find in the rain.
If you don't have a lot of time in Vancouver, you'll probably still want to spend at least a half day in Stanley Park: start out early for a walk, bike, or shuttle ride through the park to see the Vancouver Aquarium Marine Science Centre, enjoy the views from Prospect Point, and stroll along the seawall. If you leave the park at English Bay, you can have lunch on Denman or Robson Street, and meander past the trendy shops between Jervis and Burrard streets. Alternatively, you can exit the park at Coal Harbour and follow the Seawall Walk to Canada Place, stopping for lunch at a seaside restaurant.
A couple hours at the Granville Island Public Market are also a must -- plan to have lunch, and, if you have time, check out the multitude of crafts stores.
Walking the downtown core is a great way to get to know the city if you don't have a lot of time; city's easy layout makes strolling a pleasure. Plan a route that starts at Canada Place and heads east to Gastown and Chinatown; that's a good half day. Then, to complete the day, head north to Yaletown and travel back via Robson Street, by which time you'll have earned yourself a glass of British Columbia wine at one of Vancouver's excellent restaurants.
If you're traveling with children, you'll also probably want to check out Science World, Grouse Mountain, and the Capilano Suspension Bridge or Lynn Canyon.
For museums, adults and older children love the displays of Northwest Coast First Nations art at the Museum of Anthropology.
While most Vancouverites don't let a little drizzle stop them, heavier rains might inspire you to seek indoor activities. Obvious options include museums -- the Museum of Anthropology at UBC is a worthwhile trek, but if you're downtown, the Vancouver Art Gallery is good for an hour or two as is the Vancouver Aquarium. Less obvious choices are the Granville Island Market, which is inside -- you just have to get here, then you can spend hours browsing the goods and having lunch -- and the Dr. Sun Yat-Sen Classical Chinese Garden, which has covered walkways.
