Proper English

Make sure that you use proper english and do not use abbreviations, this is so that your readers can understand you easier and it looks a lot more professional too Also it is a good idea to go through the tutorial once you have completed it so that you can check if there are any errors in it (typos, spelling errors etc).

Use Steps

Use clear, concise and logical steps in your tutorial. This is so that your reader can understand you easily.

Try to have a balance of text and images, try to have an example of what the reader’s image should be looking at at each step. Most tutorials have this covered which is good

Also make sure that you do not miss out any steps so that the reader does not get left behind you and confused which leads on to my next point…

Teach Not Tell

Teach the reader how to do something, do not just tell them how to. Make sure that your tutorial teaches the reader how to use the tools and techniques so they can create more stuff afterwards, rather than a specific thing.

A good example of a tutorial which teaches the reader is Using Light & Shade to Bring Text to Life by PSDTuts. This tutorial provides lengthy explanations of the techniques and explains about the tools that they use in the tutorial.

And an example of a tutorial which just tells the reader what to do is Technical Interface by MickM.

More…

If you would like to learn how to submit a tutorial check out my How to Submit a Photoshop Tutorial post.

To have a look at some more good tutorials check out Good Tutorials which has (mostly) good tutorials on it (most of the bad tutorials are filtered out through moderation).