No semicolon between a subordinate clause and the rest of the sentence
No semicolon between an appositive and the word it refers to
No semicolon to introduce a list
No semicolon between independent clauses joined by and, but, or, nor, for, so, or yet
EXCEPTIONS:If at least one of the independent clauses contains internal punctuation, you may use a semicolon even though the clauses are joined with a coordinating conjunction.
Although a comma would also be correct in this sentence, the semicolon is more effective, for it indicates the relative weights of the pauses.
Exercises:
The semicolon and the comma 1
The semicolon and the comma 2
The semicolon and the comma 3
The semicolon and the comma 4