To Forbidden city: walk about 600 meters to Donghuamen bus station and then take bus No.62 and get off at East Tiananmen. Walk about 600 meter and you will see it.
To temple of heaven: walk to the bus station of Dengshi Kou and take subway five and get off at the east door of Temple of Heaven.
To great wall: it is a long journey.
walk to Dengshi Xikou and take 108 and get off at south Jiaodaokou. Then walk to east Jiaodaokou and take 635, get off at south Desheng gate. Take 911 at Desheng gate and you will reach Great Wall.