Honestly if you can't do it, look at your DPS, look at your rotations, then look at your gear. One of those are your problems. Either you have a weak player, someone (or some people) have a weak rotation, or weak gear build. Obviously if you aren't doing it within the time given you're just not at the point where you should be to complete the turn. Try and figure out where your DPS is lacking and fix it.
Strategy wise, mages and summoners on aoe and spider duty, physical dps on rooks.
