1. A semicolon is used to join two phrases that could stand alone as sentences instead of using a conjunction (and, but, or, nor, for, yet, so).
    Ex: The Writing Center is open seven days a week; students may make an appointment or walk in any time.

2. A semicolon is used to join two phrases that could stand alone as sentences joined by a conjunctive adverb (however, therefore, in addition, meanwhile, etc.).
    Ex: Joe didn't want to go to class because he hadn't finished the paper that was due; however, he didn't want to miss the review for the test either.

3. A semicolon is used to separate phrases that are long or contain commas.
    Ex: The Writing Center will gladly work with students who want help with improving their writing skills; with students who need assistance with citing, documenting, or researching internet sources; and with students who desire feedback on resumes, cover letters, or graduate school applications

4. A semicolon is used between items in a series if the items contain commas.
    Ex: The winners of the writing contest were: Marty Rubens, original fiction; Janet Spurlow, poetry; and Mike Jacobs, who received the award for the most creative piece overall.

1. The colon is used after an independent clause to introduce a list of items.
    Ex: The following energy sources are renewable: wind, hydropower, biomass, solar, and nuclear.
 

2. The colon may be used to emphasize a word, phrase, clause, or sentence which explains or impacts the main clause.
    Ex: Yesterday, a revolutionary new plan was unveiled to "solve" one of Xavier's most frustrating problems: parking.
 

3.  Use a colon to introduce a quotation (only if the words before the colon are an independent clause).
    Ex:  The writer offered wise advice: "Get into the habit of reading your work aloud."