If offered a collaboration, be certain of who is going to profit the most from mutual work.
Assess the power dynamic in the conversation. Pay attention to verbal formulations. Who is leading the conversation? What are their expectations? Is there enough room for discussion? Collaborative partnerships should be equal, not hierarchal.
In case you get confused during the conversation, do not be afraid to change the flow. For example, if something is left unclear for you, ask questions, clarify and identify what you aim to achieve together.
Be confident! If they approach you it means they need you.