1. Run-on Sentences.
You have to start with understanding what a clause is.
A clause is a group of words that has a subject and a verb.
There are two main types of clauses: independent and dependent (dependent are also called subordinate—the terms are interchangeable).
An INDEPENDENT clause can stand alone as a sentence.
I ate the baby.
Babies taste like chicken.
A DEPENDENT clause cannot stand alone as a sentence. (Even though it has a subject and a verb! Whaaaaaaaaa?)
While I was eating the baby.
Babies that taste like chicken

2. Types of Sentences There are four types of sentence structures Simple
Compound
Complex
Compound-Complex

3. Simple Sentences
A simple sentence consists of ONE (and only one!) independent clause.
It can have a compound subject or a compound verb, but it’s still just one independent clause.
I ate the baby.
I ate a hamburger, a hot dog, nachos, and a baby.
Tommy, Sarah, and Keonte shared the baby for dinner.
Kialani and Danielle battered and fried the baby.

4. Compound Sentences
A compound sentence consists of more than one independent clause.
It could be two independent clauses, three, or fifty. But if they’re all independent clauses, then you’ve got a compound sentence.
I cooked the baby, and I ate the baby.
The baby was delicious, so I ate the whole thing in one sitting.
The baby was delicious, the atmosphere was romantic, and the night was just perfect.

5. Compound Sentences, cont.
When you are combining these clauses, be sure to use correct punctuation.
Either use a comma + coordinating conjunction
Coordinating conjunctions = FANBOYS—for, and, nor, but, or, yet, so
You can also use a semicolon. It’s like a comma and a period had a baby.
Be sparing with your use of semicolons, though. If you use them too frequently, it’ll seem like you’re trying too hard and nobody will be your friend.

6. Complex Sentences
A complex sentence consists of ONE INDEPENDENT clause and AT LEAST ONE DEPENDENT clause.
While I was eating the baby, my mom called.
When I was finished eating the baby, I washed my face that was covered in barbecue sauce.
After I ate the baby that was a little too fatty, I took a long nap.

7. Compound-Complex Sentences
Here’s where you put it all together. A compound- complex sentence is both compound and complex. So it has at least two independent clauses and at least one dependent clause.
After I ate the baby, I watched Friends, and I read A Modest Proposal.
I was getting ready for bed, and Charlie was already asleep when the baby started to come back from the dead, which was pretty unnerving.

8. So what does this have to do with Run-On Sentences or Fragments?
A run-0n sentence is when you have two independent clauses that are joined incorrectly.
It could be a comma splice:
I ate the baby, it tasted great.
It could be missing a comma.
I ate the baby and it tasted great.
I ate the baby it tasted great.

9. So what does this have to do with Run-On Sentences or Fragments?
To fix these run-on sentence errors, add the correct punctuation or divide into two separate sentences. (or restructure one of the clauses to be a dependent clause)
I ate the baby, and it tasted great. (added comma coordinating conjunction)
I ate the baby; it tasted great. (semicolon)
I ate the baby. It tasted great. (divided into two sentences)
I ate the baby because it tasted great. (changed to dependent clause)

10. So what does this have to do with Run-On Sentences or Fragments?
A fragment? That’s simple, yo. They’re incomplete sentences.
The easiest fragments to identify are the ones that are missing either a subject or a verb.
The lady with the baby arm in her mouth
The succulent and juicy foot
Chewed for a long time
A fragment can be a dependent clause, a group of words that does not communicate a complete thought.
While I was chewing the foot
Who had the baby arm in her mouth

11. So what does this have to do with Run-On Sentences or Fragments?
How to fix fragments:
Either add the part of the sentence (subject or verb) that the fragment is missing.
The lady with the baby arm in her mouth looked very happy.
The succulent and juicy foot was on the grill.
I chewed for a long time
Affix the dependent clause to an independent one.
While I was chewing the foot, I broke my tooth.
I was creeped out by the lady who had the baby arm in her mouth.

12. Public Service Announcement
Don’t eat babies. They taste terrible.