I'm not a lawyer, but I would suggest making them as short and clear as possible. List what your expectations are for your users and what your users can expect of you. Don't make a rule that is difficult or impossible to enforce. Err on the side of caution; you might make a few users mad, but it's better than getting a cease and desist letter from a multi-billion dollar company.
For privacy, tell your users exactly who you will share their information with, exactly what information will be shared, and how they can request permanent removal of their information from your servers.
Terms of service are fairly easy; just tell your users what is and is not allowed. Make sure that you explicitly state that you have the final say in all matters and that you can change the terms at any time.
The submission agreement is going to be the most difficult one. Copyright law is extremely tricky in the first place and you're adding your rules on top of a gigantic pile of other international and national laws. You should make it clear who is the owner of uploaded content and what you do in case there is a dispute of the ownership. You should also mention what rights you have as the service provider. Can you use uploaded content to promote your site and etc.
There are many free legal advice forums out there. Your best bet would be to post your policies there and get a real legal opinion. If your agreement will not hold up in court, then there's no point in even having it in the first place.
* Moved to off-topic... can't figure out a good forum for this
*
