Subsection III.I: Grammar it Right!
How you say things in a post is very important, so it only makes sense that you say it all correctly. Use complete sentences and correct punctuation to the best of your knowledge. Periods indicate a complete stop, and commas indicate a pause. Remember that and make use of that when writing, Too many periods creates a choppiness about your post, and too many commas makes it drone on until the reader just forgets where he/she is. Check your spelling if you tend to misspell a lot of words. Many misspelled words can make your post confusing.
Another very important rule is to never use the abbreviations typical of internet language. You're writing, not chatting, and are under no time constraints. Put in effort to type out your words completely and use no shorthand.
Keep your post in the same tense (past, present) throughout the entire thing. Past tense is usually preferred, but every site and GM has their own ways. Pay attention to the tense that others are posting in, or just stick with past tense if you are unsure.