劳驾, 麻烦（您）, 对不起, and 不好意思
láojià, máfan (nín), duìbuqǐ, and bùhǎoyìsi
While living in a big Chinese city, this is definitely a useful phrase to know.
劳驾，麻烦（您），对不起 ，and 不好意思, are the four most commonly used expressions for situations that would require the phrase "excuse me." People from the northern part of China most often use “劳驾,” while people in the rest of the country tend to mostly use any of the other three. But saying one of these four phrases alone is not enough and to get through a crowd. The most common way using a complete sentence requires the addition of “让一下 [rangyíxià],” e.g. “劳驾/麻烦（您）/对不起/不好意思，(请）让一下.” This sentence can easily be understood throughout China; it sounds very polite and courteous.
In Beijing, aside from “劳驾,” people also tend to use “借过 (jièguò)” a lot, which is the abbreviated form of “借光,过一下 [jièguāng guòyíxià].” “借过” is mostly used in the northern parts of China (Beijing, Tianjin, Hebei, Shandong, Henan, Shanxi, etc), although it is considered by some to be a bit old-fashioned and is mostly used by men.
If all else fails, say “不好意思” no matter where you are and you should be fine."