Some Ideas:
Introduce some sort of artifical structure to assist organisation. Perhaps model the group on a military squad (or small mercenary band, or large surgical team, or whatever) so that everyone sort of 'falls' into a role bsaed on whatever is happening at the time.
Lots of good advice above.
Table discipline is going to be absolutely essential if you actually get 10.
Table discipline is going to be absolutely essential if you actually get 10.
Also, if you have some sort of a "squad" and a nominal party leader, consider introducing an NPC (yep, another character) whose only job is to keep the group focused - maybe a 'HQ leader' who never enters the field, but works to keep the party focused on specific goals.
In terms of the game itself: stick to straight combat or 'military' missions for a while at least. You know, clean out the kobold caves, guard a caravan, guard a person, that sort of thing. Adventures based on find the person in the big city, try and infiltrate the theives guild, etc can be a nightmare with 3 players, let alone 10.
On the other hand, if you can get 10 (or even 7) players working together as an efficient team (including being respectful of other's time at the gaming table) you will be able to do adventures that are truly grand and epic, and the the DM + 3 style group will only be able to wonder at.
Rassilon.