A comma splice occurs when two complete sentences are joined by a comma, and there is no conjunction present.

• INCORRECT: I'm taking a ride with my best friend, I hope he never lets me down again.

A comma splice can be corrected with: a period; a semicolon; a conjunction; or a semicolon and a transitional word.

• CORRECT: I'm taking a ride with my best friend.  I hope he never lets me down again.
• CORRECT: I'm taking a ride with my best friend; I hope he never lets me down again.
• CORRECT: I'm taking a ride with my best friend, and I hope he never lets me down again. 

A period between two complete sentences.

• INCORRECT:  My lease ends in September, I'll need to renew it soon.
• CORRECT: My lease ends in September. I'll need to renew it soon.

A semicolon between two complete sentences.

• INCORRECT:  My lease ends in September, I'll need to renew it soon.
• CORRECT: My lease ends in September; I'll need to renew it soon.

A conjunction.

• INCORRECT:  My lease ends in September, I'll need to renew it soon.
• CORRECT: My lease ends in September so I'll need to renew it soon.

A semicolon and a transitional word followed by a comma.

• INCORRECT:  My lease ends in September, I'll need to renew it soon.
• CORRECT: My lease ends in September; therefore, I'll need to renew it soon.
• CORRECT: My lease ends in September. Therefore, I'll need to renew it soon.