Start with the game objective
Decide which behaviour you want the game to bring out. It could be dribbling into space, supporting an attack or recovering after losing the ball. Atalanta Hexagonal SSG, Munich 3v3 Small Sided Game and Villarreal Dribble & Shoot SSG use different arrangements. Their titles are a starting point; compare the full instructions and coaching points before choosing.
Check everyone has a role
Read the complete player range rather than relying on the game format in the title. The listed numbers can include rotations or supporting roles, and goalkeepers are listed separately. Explain who starts, who supports and how players rotate. If attendance changes, review whether the same game still works before asking one player to cover several unrelated roles.
Use conditions with a reason
Direction, scoring zones and restrictions should serve the main football problem. Introduce the starting rules clearly and let the group experience them before adding more. If a condition prevents the behaviour you wanted, review it rather than layering on another rule. Use the space shown in the practice as your reference and consider what any adjustment asks the players to do differently.
Observe before intervening
Let a few comparable situations develop so you can identify a useful pattern. Choose a short question or demonstration that relates to that pattern, then restart promptly. Keep a note of what changed afterwards. A game can also help you revisit a focus from an earlier technical practice, provided the numbers, direction and scoring task give players a chance to use it.