Wikipedia:Can't break it
This is an essay.
It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints.
One aspect of Be Bold! that doesn't get stressed enough for new users is this: you can't break Wikipedia. If you're not intentionally trying to hack into the server or mess things up, you're not going to damage it.
One of the strengths of Wikipedia is that a record is kept of every edit that gets made. If you're editing in good faith, don't worry that the first time you try and edit an article, everything looks different and you're afraid to touch anything for fear that you'll break it. Wikipedia is space age Corningware, not ceramic, and it's not going to shatter if you drop it. Don't let your fear of messing things up keep you from editing.
If you mess something up, and it really looks wrong, just bite the bullet; look at the history of the page you're working on. The radio buttons of the version you were just working on, and the previous version will be highlighted. Click the button that says 'Compare Selected Versions'. At the top of your version, there's a link that says 'Undo'. Click on it, and save your change, reverting to the page before what you tried to do. Nothing is lost forever! Then, think on it, and if it was a good idea, try it again!