Hi. I will staying in Kerry Beijing. Please advise wht is the nearest subway line.

The neatest subway line is line 10. The nearest station is Jin Tai Xi Zhao.
1. Walk to Jin Tai Xi Zhao Station, take line 10 there to Guomao, transfer to line 1 to Tian’anmen West. From Tiananmen you can walk to the Forbidden City.
2. Walk southwards to Guomao Station and take subway line 1 there to Dongdan, transfer to line 5 to the East Gate of the Temple of Heaven.
3. Take subway line 10 from Jin Tai Xi Zhao to Hujialou, transfer to line 6 to Beihai North.
4. Take subway line 10 from Jin Tai Xi Zhao to Haidian Huangzhuang, transfer to line 4 to Beigongmen.
5. Take subway line 10 to Huixin West Street South Crossing, transfer to line 5 and get off at Lama temple.
6. For hutong tour, there are many hutongs in the city. I just recommend the transportation to the most famous, Badahutong. To go to this place by subway, you need several transfer. So bus would be better for you. Just walk westwards to Fangcaodi South and take bus 120 there, get off at DaZhalan. After arrival, walk to the southwest to reach.
7. For Great Wall, I would recommend you go to the Badaling. You can take subway line 10 to Zhichun Road, and transfer to line 13 to Xizhimen. After arrival, walk northwards to the North Railway Station. There you can take the S trains to Badaling directly. You can reach the Ming Tomb from Badaling by bus no. 879.
8. To Capital Museum you can take line 10 to Guomao, and transfer to line 1 to Muxidi. After arrival, walk eastwards to reach.
To the Military Museum, you can walk southwards to Guomao and take subway line 1 there. Just get off at the Military Museum Station.