Be sure to get a day pass for all public transportation--metro, buses, trams. There are vending machines in the metro. 5 euros a day--well worth it. The no. 28 tram is the 'tourist route'--take it end to end.
Casa de Alentejo, Restaurant and private social club. Fantastic moorish-inspired interiors and tiled walls. The food is good enough--we liked the bacalao spiritual. http://www.casadoalentejo.pt/
Frank Bruni of the NYTimes writes about how he fell in love with Lisbon--
http://www.nytimes.com/2012/05/27/travel/how-i-fell-for-lisbon.html?pagewanted=all
And here's his list of not-to-miss restaurants http://travel.nytimes.com/2012/05/27/travel/4-lisbon-restaurants-not-to-miss.html
We followed his tip and had drinks at the rooftop bar of the Hotel do Chiado (next to FNAC)--great views!
Our friend Ada's restaurant tip: Sinal Vermelho, R. das Gáveas, 89, Barrio Alto, tel. 213-461-252