Grammar. Blurgh. You probably want to leave this post already. Don’t. I have good news. I promise.

See, some people will tell you grammar is about rules. They're wrong. There are rules. Lots of them. But that's not what it's about.

Grammar is about clarity. About being understood. It's an ally, empowering you to say what you really mean. Giving you confidence in knowing, absolutely, that you're understood.

And only when you're understood can you connect with people on a real, impactful level. And as entrepreneurs, that’s essential to our businesses.

That's why it's important that you use grammar correctly. And note, "correctly" doesn't necessarily mean obeying all the rules. The paragraph above is riddled with technical errors. But did you understand it? Was it clear?

Using grammar correctly means knowing the options available, what you can play with and what you shouldn't, and using that to create your desired effect.

The effect of your writing is what we mean when we talk about tone of voice. It might be fun, professional, personable, romantic, quirky or anything else. But—if you're writing for someone else to read—your desired effect must first and foremost be CLEAR.

Because it doesn’t matter what you say, if no one understands it.

So which grammar rules should you use to help you write clearly? Which should you ignore?

There are several writing rules below, but it doesn’t mean the title of this post is a lie! Keep reading to find out how there really is only one rule you need. (I may have already hinted at it!)

Rules to tear to bits, stamp on and use your heal to squish them into the pavement until they turn to mush:

1. Don’t split infinitives.

Very simply, infinitives are the basic version of verbs, like to go, to see and to eat. Splitting them means shoving a word in-between the two words that make up the infinitive.

You CAN do that. Otherwise, the Enterprise would have to go boldly where no man has before, and that just sounds stupid.

2. Don’t start a sentence with a conjunction.

Conjunctions are joining words, like and, or, but, however, so and because. These days, starting sentences with these words is completely acceptable in almost all online writing.

In fact, they can be really useful in ensuring your writing flows from one sentence to the next, keeping the train of thought connected. (A disjointed train of thought is common with inexperienced writers.)

3. Don’t end a sentence with a proposition.

Many people never understood this one anyway, so good riddance. Propositions are the small words that tell you where something is in relation to another thing, like on, in, above, over, up and by. Really formal writing is the only place this rule still exists.

4. A sentence must always contain a subject and a verb.

Subjects are things. Verbs are action words. In online writing, particularly blogs, short sentences are recommended.  Shorter = easier to read. So we often split sentences up, and that’s okay.

The best blogs are also quite conversational, and in real conversations we use fragmented sentences all the time. Let your writing reflect real conversation.

Rules you should recite enough times that they slip into your dreams and hang out there every night with Channing Tatum:

1. Start a sentence with a capital letter. End a sentence with a period (full stop), comma, exclamation mark or question mark.

Don’t get too creative. You can’t screw with this one.

2. Don't separate two independent thoughts with a comma.

I see this A LOT. It feels like a stream-of-consciousness sentence running on and on. Here's what it looks like: Sophie is crazy, she broke into Channing Tatum's house and stole his underwear, she doesn't even care.

These are three separate thoughts. The simplest way to fix this is to split them up with periods (full stops). Here's how: Sophie is crazy. She broke into Channing Tatum's house and stole his underwear. She doesn't even care.

3. Get your apostrophes in the right places.

If something belongs to someone, use 's, for example: Sophie's restraining order.

If you're smushing two words together, you use ' for the missing letter, for example: Don't trust crazy Sophie (instead of do not trust crazy Sophie).

If you're talking about more than one thing, there's no apostrophe, for example: Sophie now has three restraining orders.

4. Know the difference: their, there, they're

Their = something belonging to them. Their sister, Sophie, is crazy.
There = a place. There are Channing Tatum's g-strings!
They're = they are. They're auctioning off Channing Tatum's g-strings to fund his law suit against Sophie.

The only writing rule you really need to know

But for all this, there is just one rule you need to know. One guiding principle that will serve you well in everything you write. And that’s this:

Everything you write must be clear.

Forget cleverness and humour and sophistication and creativity. None of that matters until you’ve ensured that everything you've written is clear.

There you have it. The one writing rule you need to know. Everything else will follow, but keep your clarity and you know you’ll be understood. And that’s empowering.

Our next post will be a round-up of personal advice from 12 of the internet’s biggest entrepreneurs! I’m excited. You should be too! Sign up below to get the post in your inbox, as well as The Don’t Hit Publish Until You Check This! Checklist for your own blog.