We need three things: intelligence (about our adversaries), a plan, and a way to call for reinforcements.
For intelligence, the quickest way would be to take some gnoll watching the perimeter, assuming they do such things. After we know what they’re about we can make a plan of attack.
My old commander said- there are only three sins in soldiering: wasting time, wasting ale and wasting the element of surprise.
One of you cleric types find a way to send for reinforcements.