As usual, 3-day itinery just goes like this: Day1,the Tiananmen Square,the Forbidden City and the Temple of Heaven,you can take subway lines to get there; Day2 Badaling Great Wall and Ming Tomb and Scared Way. You can take NO.919 at the gate of Deshengmen,the air-condition bus will take you there directly. Day3 Summer Palace and Lama Temple,the subway lines are also very convenient choices. Hope it can help you.