Lisbon is a most wonderful city - beautiful, gracious, fascinating all around. Charming neighborhoods to explore, full of culture and history. Diverse, from modern displays at the 1998 World Expo site to castles, buildings and monuments dating back to the 1700's and earlier.
We all hopped on the Metro, trains and buses to get around. We found the transportation quite comfortable and easy to use, though crowded at times. Portuguese isn't exactly the easiest of languages, and thus we did a fair job of mispronouncing just about everything. After a chuckle or two, people came to our rescue, not only pointing us in the right direction but helping us pronounce words and destinations correctly.
We found many locals genuinely wanting to help (and wanting to practice speaking English). I also think they were curious about us. Many Europeans vacation in Portugal, but not many Americans, thus the novelty.
Yes, explore the neighborhoods, visit the top tourist attractions and sample the wide variety of Portuguese cuisine. But my best advice: take a break at a local café, grab a coffee, a local beer or glass of wine and start a conversation with a few locals. Truly authentic travel.