To add another idea: to express an additional point

To express cause and effect: to show that one idea may cause another

To express contrast (differences) between two ideas

Introduces a dependent clause;  it must be followed by a subject and a verb

-Because

(e.g. Because the exam was approaching, Peter stayed home and studied hard every evening.)

-While
-Although
-Even though

(e.g. While the cost of living is very high in HK, food is not too expensive.)

Must be followed by a noun phrase

-In addition to

(e.g. In addition to playing guitar in a band, Jim hikes, swims and reads.)

-Due to
-Because of

(e.g. Due to the high cost of the concert tickets, John decided not to go.)

-In spite of / Despite

(e.g. In spite of the high cost of the concert tickets, John decided to go.)

Can stand alone (in front of a comma or between two commas)

-Additionally
-Furthermore
-In addition
-Ultimately

(e.g. Additionally, the government should penalize drivers who sit in their vehicles with the engine idling. / The government should penalize, additionally, drivers who sit in their vehicles with the engine idling.) 

-Consequently
-Therefore
-As a result

(e.g. John did not study for the exam. Consequently, he must repeat the course to make up his failure. / He must repeat the course, consequently, to   make up his failure.)

-However
-On the other hand
-Nevertheless

(e.g. Mary did not go to university. Nevertheless, she found a well-paid job. / She, nevertheless, found a well-paid job.)