Shopping:
Zainab Market: great for bargains. The trick however is to make sure you have a local person with you so that you are not charged double the normal price. Haggling is the norm!
Juma Bazar: a very "traditional" open air market is the Juma(friday bazar)- you can get EVERYTHING there but beware of pickpockets
Urdu Bazaar: a wonderfully huge bazaar for books. The collections there are wonderful, though about 80% are in Urdu or Arabic
Sadar: ahh, the true flavor of shopping/haggling in Karachi. Don't forget to visit the jewelry stores
Tariq Road: Something for everything kind of shops
Try and go crabbing or for camel rides on the beaches. There are private beaches available for non-Pakistanis [or for very wealthy Pakistanis!]
Quick Tips:
Women should be careful about traveling alone.
Best Way To Get Around:
Driving is perhaps the easiest if you know the roads and can stand maniacal driving- people do not follow traffic signals very closely, and dont ever try to cross the road at a cross-walk. You'll be safer weaving between the traffic. Taxis are available but it's better if you dont travel in them alone. Try the rickshaws rather than the buses- and you can't beat the put-putting sounds they make.