Content is more important than presentation
If you're not a great writer, don't sweat the small stuff. It's more important that you share those good tips and techniques you've figured out than it is to look like a professional writer. Sooner or later, someone else in the community might find time to improve the grammar, spelling, presentation, etc.
When creating a new article, follow the brown-colored guidance text in the template as well as you can
But again, don't sweat the small stuff. The templates won't cover every type of article you might want to create.
Avoid deleting content entirely
If you feel that an article is too bloated and you're tempted to trim the things that you find "extraneous", you generally should not do this. Instead, you should move the information that you feel is "extraneous" to a new page and then provide appropriate links from the original article to the new page(s). This way no potentially useful or important information is lost, but you have achieved your goal of streamlining the original article.
Explain your reverts and removals thoroughly
Unless the revision that you are reverting or removing is obvious vandalism, you must post a comment in the article's discussion thread that provides your reasoning for reverting/removing the content. And don't forget Bill & Ted's Golden Rule. See the Conflict resolution policies section below for more information.
Most importantly, remember that assuming "bad faith" on the part of the person who made the revision you're about to revert can blind you from making an objective assessment of their revisions. This can result in good content being lost from the wiki.
Obvious vandalism should be removed quickly
Obvious vandalism, personal attacks, and other explicit policy violations are of course things that should be reverted as soon as they are noticed. Don't wait for an admin or moderator to fix stuff like this; it's your wiki too! Please step up to the plate and fix problems like these when you encounter them.
We are not Wikipedia
Do not revise an article for the express purpose of trying to make it conform to Wikipedia's editorial guidelines and policies. We are musicians, not a lynch mob of rabid Wikipedians. If you revise a existing article, it should be for the simple purpose of adding more useful information, correcting mistakes, or perhaps making a roughly-written article a bit easier to read.