You are getting some good suggestions. Here are a couple more.

Guidebooks. I rarely follow the suggestions for restaurants or hotels but they almost always have information on things to see or do that I wouldn't have thought about. My preference is Frommer's Guides because they normally have decent maps and suggested walking routes. Everyone's likes and dislikes are different and you may prefer the style of another guide series. Try browsing the travel section in a large book store to get an idea of which guides you might like.

Don't forget to scroll down to the "Travel & Dining: Destination >> ??? section here on Flyer Talk. Some of the subgroups are pretty quiet but others have a wealth of information about specific destinations and some very savvy FTers who can give great advice hang out there.

JR