1. The Semicolon (;) and the Colon (:)

2. 1st use of a Semicolon
The first appropriate use of the semicolon is to connect two related sentences. The pattern looks like this:
Complete sentence  + ; +  complete sentence .
Here is an example: My eighty-one-year-old grandmother still rides her Harley motorcycle; her toy poodle balances in a basket between the handlebars.

3. 2nd Use of a Semicolon
You can also team up a semicolon with a transition to connect two complete sentences that are close in meaning. The pattern looks like this:  Complete sentence  + ; +  transition  + , +  complete sentence .
Check out this example: My father does not approve of his mother cruising around town on a Harley motorcycle; however, Grandma has never cared what anyone thinks.

4. 3rd Use of a Semicolon
Finally, use the semicolon to avoid confusion when you have complicated lists of items. The pattern looks like this:  Item  + , +  More Information  + ; +  Item  + , +  More Information  + ; + and +  Item  + , +  More Information
Read the following example: On a Harley motorcycle, my grandmother and her poodle have traveled to Anchorage, Alaska; San Francisco, California; and Tijuana, Mexico.

5. Reminders about Semicolon Use
Keep these three things in mind when you use a semicolon:
 The two main clauses that the semicolon joins should be closely related in meaning.
 Don't capitalize the word that follows the semicolon unless that word is a proper noun, one that is always capitalized.
 Limit your use of semicolons; you should not scatter them wantonly throughout your writing. Semicolons are like glasses of champagne; save them for special occasions.

6. Use a Colon…
after a complete statement in order to introduce one or more directly related ideas, such as a series of directions, a list, or a quotation or other comment illustrating or explaining the statement. For Example:
The strategies of corporatist industrial unionism have proven ineffective: compromises and concessions have left labor in a weakened position in the new "flexible" economy.

7. …to introduce a list…
The daily newspaper contains four sections: news, sports, entertainment, and classified ads.

8. between the hour and minutes.
He said he would be at home by 5:30 p.m.

9. between chapter and verse in biblical references.
He always liked to refer to Genesis 1:18 when starting a speech.

10. Caution
Space once between a colon and the next word, when the colon is used between words. Do not space between numerals and a colon when a colon is used to mark time or ratios.