the ball is in your court
hit below the belt
learn the ropes
out of one's league
skate on thin ice
throw in the towel
hit the ground running
set the ball rolling
keep your eye on the ball
it's not cricket
in the long run
knock yourself out

give up
learn to do something
not fair
eventually
do a lot of work
focus
it's your turn to make a decision
be successful from the start
say something mean
not in the same class or category
in a dangerous situation
to open, to start something