• Use it to join two independent clauses (IC; IC.)
  We were hot and tired; we had been outside all day.
• Use it before a conjunctive adverb that is joining two independent clauses (IC; ca IC).
  We had been outside all day; therefore we were hot and tired.
• To separate items in a series already containing commas:
  We sat on the cold, wet sand; played in the rough, rolling surf; and slept on our warm, dry towels.

The colon :

• Use to introduce a list, but not with words like “such as” or “including.”
  I was happy to see my grades: two As and a B.

The dash –

• Use it to add or set off information.
  We were glad the teacher—usually crabby—was in a good mood for grading.