I am first time visitor to Beijing. Is there any scam I should avoid during visit?

As first time visitor, many people will suggest you to look around at Wangfujing Street near Forbidden City.  If a young girl says hello to you and wanna know you to learn English and then invite you to have a drink in a cafe or bar and maybe to do more later.

you should not go with her. Otherwise maybe you will get a big bill after finishing and the girl was gone.  Why not spend a clear and fixed amount of money to enjoy a time of fun with an escort?  This is fair business. 

But you should not think this is China's particular scam.  It does exist in many places.  One Japanese customer said he was trapped several times even in his own country.