A short preparation routine can remove many avoidable problems before a mission begins.
Check the primary loadout
Make sure the weapons you intend to use fit the build and are ready for the mission.
Check recovery options
Do not discover during a difficult encounter that healing or defensive options are missing.
Check cyberware synergy
The setup should reinforce one coherent play style rather than several unrelated ideas.
Leave room for rewards
Inventory space makes post-mission comparison and cleanup much easier.