Comma splices: using comma wrong when a writer try to connect two main clauses.
I have to work hard, final exam is coming soon.
I have to work hard, because the final exam is coming soon.

Run on sentence: two or more independent clauses are connected without an appropriate punctuation or conjunction.
I went to see Mr.D I talked about how to improve my grade.
I went to see Mr.D and I talked about how to improve my grade.

Sentence fragment: sentence that can not stand by itself. It doesn't have any independent clauses.
Tired so didn't finished the homework.
I felt tired so I didn't finished homework.

Independent clause: a clause that can stand by itself.
I love you

Dependent clause: a clause that provides an independent clause with additional information,but which cannot stand alone as a sentence.
She is a beautiful girl who is sixteen years old.