Okay, this mini-lesson is about things that are pretty technical. What I'm about to say isn't really set in stone, as some writers do it in different ways, but these are just the rules that I follow, and I hope it'll help you too.

I'm going to start by playing the role of an English teacher for a few seconds. Each sentence should have a subject, and a verb. Every thing can be added and changed to your likely, but for the sake of making complete sentences, you should aim to have a subject and verb.

Examples:

I ran.

I ran to my house.

I ran quickly.

I ran with her.

I didn't know what to do, so I ran.

However you put it, each of these sentences has a subject (I) and a verb (to run). It works every single time, I promise.

In addition, writing sentences without a subject or a verb will be considered as a fragment and will make your writing look choppy.

Examples of fragments:

Dangling my legs.

Flipping my hair.

Looking over my shoulder.

Why are they fragments? Because they are missing a main clause. They are missing that subject-verb interaction.

To fix these fragments, one could say...

I took a seat on the dock, dangling my legs over the edge.

She flipped her hair over her shoulder.

Looking over my shoulder every once in a while, I continued to run with all my might.

As you can see, these sentences make a lot more sense and they are complete in the fact that they have a subject, verb, and a direct object.

Important tip: If you write on Microsoft Word, they will usually underline fragments in green. If you come across such, read over the proposed fragment and try to understand why it is a fragment and not a sentence.

Something else I'd like to spread light on, is that your sentences should have flow. They should go together. They should be cohesive. I'll give you an example of a choppy paragraph and a cohesive paragraph.

Choppy: I had a bad dream. I woke up. It was nine o'clock. I got out of bed. I turned on the light.

Cohesive: It was minutes to nine when I woke up from a disturbing dream. It was the third time this week I had awoken from a nightmare and just like all the other times, I soon found myself inching out of bed and flicking on the nearest light to battle the demons of the dark.

Obviously, I added a few more details to flesh it out but that's all inclusive in trying to be as thorough and cohesive as possible. Details make it less choppy.

Another way to avoid choppy sentences is to have sentences that are short, some that are long, some that are combined with conjunctions and commas. If all of your sentences start with "I did this... I did that..." then it can become a little hard to read.

And lastly, this should go without saying ... But ALWAYS capitalize the first letter in a sentence and ALWAYS capitalize the letter "I"

I beg of you.