Burning the candle at both ends
To work excessively hard.

Biting off more than you can chew
Taking on more responsibility than one can handle.

Counting your chickens before they hatch
Assuming success before it actually happens.

Keeping your options open
Not making a final decision, allowing for more possibilities.

Hoping for the best
To wish for a positive outcome.

Having high hopes
To have great expectations for the future.

Setting the bar high
Establishing high standards or expectations.

Waiting for the other shoe to drop
Anticipating something negative to happen after a positive event.

Expecting the worst
Anticipating a negative outcome.

Seeing the glass half full
Having an optimistic perspective.

Playing it by ear
To act according to the situation rather than following a plan.

Waiting with bated breath
Waiting anxiously or eagerly for something to happen.

A silver lining
A positive aspect in a negative situation.

Raining on someone's parade
Ruining someone's plans or expectations.

The calm before the storm
A quiet period before a crisis or a difficult situation.

Crossing your fingers
Hoping for good luck or a positive outcome.

Walking on eggshells
Being very careful not to upset someone.

Dreaming big
Having high ambitions or goals.

Building castles in the air
Making plans that are unrealistic or unlikely to happen.

Having your head in the clouds
Being unrealistic or not paying attention to reality.