[header] How to do creative writing with a friend [title] Choose your collaborator wisely. [step] Your reason for writing together should be that each of you brings something to the project that the other could not. If you're writing a space romance and one of you provides the knowledge of astronomical distances and rocket propulsion systems while the other provides the knowledge of human interaction, you probably have the makings of a good partnership. 
If, however, you have different, and strong, ideas on writing styles, you probably will spend more time arguing over writing than actually doing it. [substeps] The above assumes you're both new writers.