Beyond the wildest dreams

Example
Trust me, this business can make a profit beyond the wildest dreams

As if I cared

Example
He behaves as if I cared to all his whims

You never know

Example
You may never know what results come of your actions, but if you do nothing, there will be no results

One good turn deserves another

Example
He fixed my tv so I let him use my swimming pool, one good turn deserves another

Upper notch

Example
The iPod Touch sets the bar an upper notch by expulsion of the traditional trackball

To hold sway

Example

Despite age his career is still brilliant, besides he holds sway over several colleagues in the company

With the hindsight

Example

With the hindsight, with today's conditions, we should have cancelled the show

A shot in the dark - stop guessing

Example

Stop guessing, it's just a shot in dark , you don't have an idea about the correct answer

Head over heels (in love)

Example

They met at spanish class and  fell head over heels for one another right away

In deep water - water up to the ears

Example

The public debt is unsustainable, Greece is in deep water (has water up to his ears)

Each to his own

Example
My cousin is a strict vegetarian I personally can't help eat meat, but each to his own.

Money talks

Example
It's a shame but nowadays, money talks

To do something until you are blue in the face

Example

I insisted until i was blue in the face, but Kevin is so stubborn that he will not listen even

To brace oneself - batten down the hatches

Example

Keep vigilant and batten down the hatches