First of all, what is a "comma splice"? Very simply, it’s the joining of two independent clauses with a comma, but without a coordinating conjunction. Here are a few examples:

• We bought a lot of chocolate chips on sale, my wife is baking cookies today.
• I’m hungry, I don’t want to fix anything too complicated.
• I looked at my weekly word count earlier, I was a couple hundred words below my goal.

Many of you may see those as examples of "run-on sentences," which they are. There are a lot of other ways to create run-ons; a comma splice is one of the simplest. 

Earlier, I mentioned "coordinating conjunctions." Coordinating conjunctions are and, but, or, for, nor, yet, so.  Each of the examples I gave can be fixed by inserting a conjunction:

• We bought a lot of chocolate chips on sale, so my wife is baking cookies today.
• I’m hungry, but I don’t want to fix anything too complicated.
• I looked at my weekly word count earlier, and I was a couple hundred words below my goal.

Note that the comma is still required before the conjunction, because the clauses are independent, or unrelated.

I’m sure many of you figured out different ways to eliminate the comma splice besides using conjunctions. For example, instead of trying to join the two independent clauses, you can simply make two sentences: "I looked at my weekly word count earlier. I was a couple hundred words below my goal." This is probably the easiest "fix," but it doesn’t always have the desired effect.

Likewise, many of you probably came up with another alternative: the semicolon. Use a semicolon if the two independent clauses are related to each other, and you want to add variety to your sentence structure:

• I’m hungry; I think I’ll fix some lunch.
• I looked at my weekly word count earlier; I was a couple hundred words below my goal.

In short, then, there are three ways to correct a comma splice:

• Use a coordinating conjunction after the comma.
• Use a period instead of a comma.
• Use a semicolon instead of a comma.

Two-Minute Drill: The Comma Splice is a post from: Kestrel's Aerie