Use the game timer.

I cannot tell you how irritating it is to see everyone around me make up great plans and have them all fall to pieces with people going "should we go? wait was that go? where should we be now?".

When I take charge of a team's planning, the first thing I do is coordinate every single effort by the timer.

The second major thing I do is have people designated teammates, partners if you will, that will keep them working together in a union rather than a free-for-all when the sky comes a falling down.

So here is an example that works very well, and makes the entire team feel absolutely great.
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CT's have arrived at the front door of the house on Militia, XYZ teams are still alive because we R0X0R (TM).

I have X go to the roof, Y go to the back-door, and Z hold position out front on the main door. It is currently 8:20 by the time I begin to explain the tactics.

X will, on the 7:30 mark, drop in through the roof and charge downstairs into the living room.

While this happens, Z will, also on the 7:30 mark, chuck an explosive, smoke, and flashbang grenade into the connecting hallway.

X will secure the living room.

X, at 7:18, will throw one flashbang grenade into the hostage area.

Then at the 7:15 mark, team Y will kick open the back door and cause a nasty distraction, at which point X and Z will move in through the hallway to finish off whatever remains.
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Obviously this doesn't end the map, but it is a great entering strategy that is still hard to stop even if the enemy knows that it is coming. The best part about the timer is that it removes the human element of error that is so tragically common with verbal go-codes. Individual teams of two are also a great way to foster communication and teamwork between individual players while also effectively doubling the tactical options by having two players with full loadouts able to share with one another.

Anyway please post your thoughts, I'd like to see some more attempts at using either of the two suggestions I have.
-Zephyr