I've only ever signed one sponsorship contract before, it's a little different than hook ups. I've had to think of all the consequences of my actions and how they'd affect my sponsors image, along with my image. It's just something to think about.
If it's sponsorship contract, think of it as your job, you don't want to fuck up.
The absolute most important part of this article is saying READ the contract. So many people sign stuff without reading it... and this is where fine print gets you.
No matter how long or complicated the contract is read it through before you sign it. If you have questions then ask a lawyer.