Shanghai is a vibrant city, the suitable time to visit in a year will be during autumn (~End of Sept to early Nov) and spring (~Mid Mac to early May). Yet recently this time period transition has become less obvious.
For last year, early autumn comes with some rains, when coming to winter it become less rain, but the day time is shorter. it get dark around 4.30 pm. For mid spring, it get bright around 5.10 am.
French concession is a good place to wander around. Various beautiful landscape / buildings.
The bund (外滩
offers the iconic view of Pu Dong (浦东
.
Jin Mao building at Pu Dong gives you a beautiful view of Shanghai. Personally I suggest go to Jin Mao and you can see the Dong Fang Ming Zhu (东方明珠
, but not the other way round.
Short day tours to vicinity area of shanghai is a good choice, example Zhu Jia Jiao 朱家角, Zhou Zhuang 周庄, and many more. Go shanghai stadium travelers meeting point (旅游集散中心
to find out more.
Public transport in Shanghai is relatively cheap.
However, my personal opinion, don't go now, maybe wait until next year's spring or autumn, as recently a lot of construction work for the 2010 world expo (May), so various scenic location has been covered with those construction stuff, not good for photography.
Last but not least, a friend of mine working in travel industry said that travel to China is best to do by following travel agent / tours from here, to get cheaper deal.
But I like self control of my time.