One of the first steps to take before deciding to collaborate with another person is making sure you are confident in not only your capabilities but there’s also.
Why? Because some people do work best alone and some people are happy to take partial responsibilities on any given project.
Communication. Communication. Communication. Make sure you are happy to communicate with any prospective collaborators using complete transparency. You can use free programs such as Slack, Skype or Email for this. Communication is key as two working styles are merging into one and you would want to make sure this is interpreted as best as possible.
Contracts! Make sure a contract is in place stating the percentages in terms of costs and profits (if required) as well as the terms of product (ownership, intellectual rights etc)