This page contains some tips that can help you get started in the role-playing world. To create a list of all the 'rules' and 'dos and don'ts' would take a lot of dedication, so your best bet would be to find a site dedicated to role-playing tips.
1. Use capitals and punctuation. This way people can at least read and understand your post. Otherwise you tend to get long-winded. If you haven't learned about capitals and punctuation in school yet...there's nothing I can do to help you.
2. Refer to your wolf in third person. "i looked at you and grinned" is one of the biggest mistakes you can make when role-playing (Look! No capitals on the 'i' either! *gasp*) People will enjoy role-playing with you more if you at least take the effort to post something like this: "She looked at the other wolf and grinned shyly." Nice, easy and simple. After you get the hang of that, it's on to more descriptive sentences.
3. Follow the rules. You can find yourself kicked out pretty fast if you repeatedly do something wrong. Generally you shouldn't post in reply to yourself within minutes of your first posts. It's very irritating when someone does that.
Writing at an Advanced Level: An Idiot's Guide
A very detailed role-playing guide. Some of the examples are human-orientated since this is from a Harry Potter RPG, but the advice is sound.
Writing Mary Sue
From the same site as the above. Explains in detail what a 'Mary Sue' character is and why it's not a good idea to play a Mary Sue.
This list is slightly out-dated. Fancy terms are frowned upon by more advanced role-players, so this list is here more to help you look up terms you see people use but don't understand.