Day 1

Day: Qianmen for people gazing.  Do veer into the small lanes for some interesting sights.  In fact, you can also rent a bicycle to venture around the area.
There are many Chinese restaurants and a few fast food food restaurants.
Subway station: Qianmen
Night: Nanluoguxiang.
Very nice stroll for some unique sights.  You can also get some snacks from the stalls.  If you fancy dining in courtyards, there are a few Chinese restaurants offering that experience.
Day 2

Day: Dong Wu Yuan Pi Fa Shang Please do not mistake this with the zoo, even though is wholesaler is located very near to the Beijing zoo.  Hence, my recommendation is if you really need to see some pandas on this trip, do so very early in the morning to beat the crowd.  After that, you can proceed to the wholesalers. 
A note of warning: there are  many pickpockets in the zoo. They prey when you are least aware, for example, when you are taking photographs.   They move so fast that you are unaware of any movements.  Before you know it, they have already gone off with your cash.  
The wholesalers are located in a few buildings. Bring a big bag to contain all your purchases because these stalls give very flimsy plastic bags which will give way even before you reach home.
The deals are good.  You can get two sweaters for as low as rmb 19.  How cheap can that be! For that kind of low prices, you have to put up with obnoxious attitude of the stallholders.  To me, it is all worth it.
There are throngs of people at the wholesaler market.     Keep your valuables close to you.   Be careful when you take out your cash to pay for your items.  Put the big notes in your bag and some small notes in your pockets.  Avoid flashing your stacks of cash in public.  Do  bring a bag to contain your valuables. The best is to bring those big and durable plastic bags.  They can definitely contain a lot. 
If you find half a day is not sufficient for you, you can come back at another time.  The wholesalers apparently open at 6 am.  
Outside the wholesaler buildings, there are a few food stalls, selling grilled meat and seafood, bubble tea and noodles.  The stall 奶茶嫁给粉 is exceptionally popular among the locals. It is an amusing sight to see these locals with huge bags of purchases sitting on the steps eating the noodles and drinking bubble tea. 
Subway station:  Beijing Zoo 

Night: Houhai
Houhai has an interesting collection of bars and restaurants.  Even if you do not like alcohol, you should take a stroll along the lake.  
Upon arrival, you can catch a group of old folks playing a game with table tennis rackets and a Chinese shuttlecock.  There is a Starbucks cafe at one end.  Most of the pubs have live music for aspiring singers.  There are a few singers who are good enough to cut a solo album.
Day 3

Day:: guided tourForbidden City / Summer Palace / Temple of Heaven
A good guide is essential because he or she can make history come alive for you.  
Night: Hotpot dinner
After a long tour, reward yourself with a good hotpot dinner.  Some people think hotpot is boring since everything is just cooked in a pot.  On the contrary, with the right soup base and sauce, the meat, seafood and vegetables can taste so good. Drink the soup last because it is extremely tasty at the end.
Local recommendation:

1. Dollar Shop (my favorite)The food is reasonably priced.   A good cut of beef costs nothing more than rmb 60.  The portion is huge by the way.  For other dishes, you can ask for a small portion.  Thus, even if you are alone, you can enjoy a hotpot.  I strongly recommend the peanut sorbet for dessert.  The peanut and ice are blended together to produce a very smooth texture. Oh, it's heavenly!
The queue can be quite long. So be there before 530 pm or after 730 pm.  To entertain the guests during waiting, the restaurant has provided board games and computers.  There is also free wifi.  Hence, the wait can never be boring.  Also the service staff try their best to be efficient.
2. HaidilaoThe following address is taken from the Internet:
Location 1: No.2 Huayuan Donglu, north to Mudan (peony) Hotel, HaidianTel: 010-62033112 

Location 2: No.29 Nanmofanglu, ChaoyangTel: 010-87798911/87798677 

Location 3: 3F, Beiao Mansion, Jia 2 Huixin Dongjie, ChaoyangTel: 010-84639300/83273345 

Location 4: No.2, Dahuisilu, HaidianTel: 010-62133511 

Location 5: 1-2F Zhongjian Erju Building, No.42, Guanganmen Nanjie, XuanwuTel: 010-51816880 

3. Kou Fu Ju I do not exactly like this one even though it is strongly recommended by the locals.  The cut of the meat is not as good as Dolar Shop.  Also, the place looks old.
4. Little Sheep

Day 4

Day:day tour to Great Wall and Ming tombs
There are a few areas where you can view the Great Wall. Badaling is near to the city.  If you do not feel like travelling far, just go to Badaling.
At Mutianyu, you can see the Great Wall and also the red leaves during autumn.
Beware that there are many people at the Great Wall, regardless of which section you visit. The steps can be steep. Hence, bring a small bag to contain your valuables.  A good pair of walking shoes is essential.  Wear a good windbreaker because the wind can be awfully strong up there. 
Night: Wangfujing Street
Any tourists should visit Wangfujing shopping street even if you have no intention to buy anything. There is a building selling children's stuff such as cartoons in Mandarin.  The Mandarin books are inexpensive.  This is also the place to find insects for sale.  Try them if you like.  Apparently the cocoon tastes like egg yolk except it is crunchy.  Anyone?

Day 5

Guided tour: Bird Nest / Lama Temple / Hutong tour
The Lama Temple is unique because it houses three different types of religions under one roof. Many locals pray at this temple.
How can visitors not view the Olympic stadium used in 2008 Olympics?  Since the area is vast, visitors can take a tram ride around the area.  
The Hutong tour is extremely interesting, especially for visitors who are not familiar with the Chinese culture.  The word "Hutong" originates from Mongolia, meaning water well.  Hutongs have been in existence for 800 years.
People staying in hutongs share a common bathroom.  That means when they need to shower or use the bathroom, they need to leave their house to walk to the nearest public toilet.  Imagine the inconvenience.  During winter, residents will use a portable toilet in their homes.  The next day, they will dispose the "waste material". The tour takes visitors to one of the locals' homes, a rare opportunity.  
It should also include a home-cooked lunch, consisting about seven dishes.  The lunch is scrumptious. 
Night: Peking Duck dinnerVisitors must eat the Peking Duck in Beijing.  There are many restaurants serving this famous dish.  Below are some recommendations:
1. 1949 @ SanlitunStrong recommended by an executive chef working in a hotel, the restaurant is extremely popular.  Reservation is strongly recommended.
2. Da Dong Roast Duck
3. Quran Ju De

Day 6

Day:: leisurely tour in the cityTake a tour in suburban areas such as Wudaokou. The Beijing Language and Cultural University Iocated in Wudaokou. Needless  to say, there are many students, both locals and foreigners hanging out in this area.  If you want to do more shopping, you can visit the clothing market there.  There are a few cafes where you can just chill and read a book. An example is SPR. 
If you need more shopping, Dongwuyuan is just a few stations away.
Subway station: Wudaokou
798 art zone 798 art zone requires at least half a day to fully tour the area.  It is a refreshing change from the hectic city life.  Cafes can be found anywhere in this zone.
Shopping mallsWant to see the huge malls in Beijing? Try Sanlitun village, Xidan or Guomao.  
Additional notes

1.Try getting the Chinese sim card at the airport.  Otherwise, it 's going to be difficult to get a sim through the proper chanel outside.

2.  Avoid taking the subway during peak hours. It is extremely crowded.  On top of that, you need to queue to get your bags checked. That adds to the hassle.