[1]Make clear contracts for partnership — profit and loss shares must be agreed upfront.
[2]Be honest with partners — the Prophet said Allah helps partners if they do not betray. (Bukhari 2218)
[2]Contribute capital, labour, or both as agreed in the partnership.
[2]Know the types: Shirkat al-Aqdan (contract based), Shirkat al-Milk (joint ownership).