Collaboration is the fastest way to learn new techniques and break out of creative ruts. But working with another producer requires a clear workflow and even clearer communication. Without a plan, a collab can quickly become a graveyard of unfinished projects.
The "Draft" System
Decide who is taking the first "draft." One person starts the groove and the basic arrangement, then sends the project (or stems) to the other. This prevents the "too many cooks" problem in the early stages. Once the core idea is there, then you can enter the "iterative" phase where you swap the project back and forth.
Stem Hygiene
If you aren't using the same DAW, stems are your language. Develop a naming convention: "BPM_Key_InstrumentName_YourName." Ensure all stems start at Bar 1, Beat 1. There is nothing more frustrating than trying to align 40 unlabelled audio files. Also, provide "Dry" and "Wet" versions of important elements like vocals or lead synths.
The "Final Say" Agreement
Before you start, agree on who has the "final say" on the mix and the master. Or, better yet, agree to send it to an outside engineer. This prevents ego clashes during the final 5% of the project, which is often the most stressful part.