Organize your party by showing which characters are where.
Show marching order for a 10' passage, a 20' passage, door openings, etc.
Always prepare for rear actions as well as frontal combats.
Assign one individual as leader.
This character will "call",
i.e. tell the referee where the party will go and what they will do.
Miniature figures are a great aid here.
The DM will usually require a marching order to be drawn on a piece of paper if figures are not at hand.