Ihave to write an essay with all these
-down in the dumps
-keeping us in the dark
-isn't all it's crocked up to be
-poor company
-caught my eye
-take things easy
-right up my street
-off the beaten track
-come down to earth with a bump
-in his element
-the crack of down

me

Basically:

Down in the dumps: sad, feeling 'down'

Keeping us in the dark: retaining or withholding information

Isn't all its crocked up to be: It isn't as good as it seemed to be

Poor company: dislikable or untrustworthy companions

Caught my eye: caught my attention

Take things easy: not to overwork yourself

Right up my street/alley: Within your skill/talent range

Off the beaten track: in or into an isolated place

Come down to earth with a bump: Coming back into reality and having to face a hard / dislikable truth.

In his element: within a place/situation he's comfortable with, suck as a skill or talent

The crack of dawn (im assuming): At the very beginning of the day when you first see the sun

  I sincerely hope this helps! Idioms are wack