quarterback

to lead, manage

Example:

Maria quarterbacked the department after Tony left.

quick-and-dirty

something done quickly and without care

Example:

I hate the website. He's done a real quick-and-dirty job on it.

quick fix

a solution to a problem that is probably not very good or permanent

Example:

The modification is no more than a quick fix. We need something better.

quick one

a quick drink - often a beer

Example:

Let's go for a quick one. The movie doesn't start 'till 8.

quit while one is ahead

to stop doing something at a point where the task is a success

Example:

The product was not that good, but the company quit while they were ahead and made a lot of money out of it.