1. Sentence Length

Keeping your sentences' length to a good "level" is one of the first tips you should earn when you write, no matter the purpose (school, law, job applications, blogging, etc.). It is not so much excessive length or extreme briefness that can go wrong, as it is inappropriate length.

A series of short sentences do not necessarily make action seem faster. It rather makes it appear broken into pieces, "chopped up", which, while it can be your wish, is not always a desirable effect.

Longer sentences with carefully chosen words can create beautiful descriptions of landscapes. "Chopped up" sentences, as I mentioned above, can create the ambiance of a confused, near-death person whose thoughts wander around a room. Let's try describing a landscape with such sentences.

There were many trees. All of them were quite big. In the middle of them was a house. It was not very big, but it was pretty. It didn't seem to be occupied. Around it ran a fence. On the other side of the fence was the main road. From the main road started a path leading to the house's door.

Now let's try spicing up that text a bit for a better rendering.

Alongside the main road was a wooden fence and from this very road started a path leading up to the house. It was a pretty house, although rather small. It appeared to be vacant at the moment. All around it were several large and healthy trees.

I have not used such terribly long sentences as I'm capable of doing, yet I have managed to make the text appear less like a log entry in an explorer's book. Let's now look into an example of good sentence chopping.

The door is closed. My stomach hurts. I look at my hand and it's covered in blood. Doesn't matter, go back to holding my stomach. The window is dirty. The floor is covered in junk. I can barely walk. I keep stumbling. I don't want to fall over or I won't be able to get up.

See? Short sentences that are perfect in a context where the character couldn't possibly stay focused for more than 10 seconds.

2. Know Your Mistakes

As a writer, it is important to be aware of the mistakes you tend to do. I, for example, have the habit of placing a comma before the word "and". I know I shouldn't, but it comes naturally. It is important, then, that I re-read what I have written (and have someone else read it too) to make sure I don't put in commas that are not needed.

3. Read, re-read and proof read

It's important to read what you have written. Read it immediately afterwards, read it two months later, read it a year later. Check out for mistakes, annoyances and, of course, for good points. By letting some time go between the time of writing and the time of re-reading, you can get some distance which will help see what is good and what is not so good in your text.

4. Let The Flow Run

While it is important to watch for mistakes, it is also important to let the flow run when it comes. If you have a good idea for an event or a bit if dialog, go ahead and write it now. Leave grammatical errors to be corrected once you're done. This will help your text greatly, as it will be more natural. It will also prevent the frustration of losing track of your idea.

Voilà, these were a few tips presented by me to you. I might do more later on, but for the moment I think it sums a slightly more technical aspect (i.e. no tips on character creations or whatever). So go ahead and write!