Properly proofreading documents before you release them is essential to creating a good and easy to play game. Proofreading makes your rules and game look far more professional, easier to use, and less likely to require errata or rules changes in the future.
There are several levels of proofreading, and whilst it’s not important to always do all of the levels, it’s important to know when to perform what level of proofreading.
The first degree of proofreading is where you simply re-read the document once you have completed it. This sort of proofreading will probably pick up some of the most obvious mistakes, and help some of the clumsy phrasing. It won’t pick up all of the errors though, as you are familiar with the work, you will read what you expect to see, and miss some very major errors.
The next level is getting friends or play-testers to read over documents. These check might find some spelling or grammatical errors, but this kind of proof reading will mainly pick up areas of uncertainty and unclear sections. This should help you clean up the weaker areas of the document.
The final level is to have you document read by a professional proofreader. This is essential for any document that you are intending to print from a professional printers. The cost involved is high, and you simply cannot afford the mistakes that will be missed if you are the only person who proofreads the document. If you are attempting to produce a professional document, it needs to be professional looking in all ways.
Finally, don’t forget to have all of the amendments you make properly proofread. It is easy to include mistakes in any changes you make to your document, and it looks just as bad to the reader.