Wikis only work if people are bold. Go ahead—change something here, edit something there, correct a mistake, add a new perspective, improve the language, or whatever you like, as long as it is in the spirit of improving the wiki. That's what wikis are all about. It's what you are expected to do. Even if it is not the best it can be, it is still good to put something down because chances are other people will come along and help to improve it. Over time, things improve. Surprisingly, it is something that actually works as long as civility is maintained.
You'll quickly notice the "natural" and understandable impulse of authors to "own" and protect their writing; this is counterproductive when it comes to wikis. It is a good idea to get rid of that tendency by being open to other people's edits. That's the only way a page will improve over time. Think about it: you might not know every perspective and every angle of a subject. Regardless of how thoughtfully you work, an additional set of eyes will always find something to improve. So, be bold not just when editing other pages, but accept other's edits on your "own" work as well.
Be bold does not mean be radical: substantial changes should be verifiable. Significant changes in the structure of a page or working of an internal procedure should be discussed on the appropriate talk pages.
Remember fortuna favet fortibus (Fortune favours the bold).
Good luck and be bold! You can do it!