The most important thing is figuring out why you were disabled, do you use adsense with anything besides your YouTube channel(s)? Once you've determined where the invalid click activity is coming from, then you can write a good appeal based on that. There is no point writing an appeal to google stating that you did nothing wrong, as they know that isn't the case, what you need to do is figure out where your invalid activity is coming from, why it's coming from there (that wasn't your doing), and how you are going to correct it.