ill at ease - uncomfortable
in hot water - in trouble
in the air -uncertain
in the dark - keep someone without knowdge; information from somenoe
in the lone run - looking toward the future; eventually
ins and outs - all the details; the various parts and difficulties to be seen
iron out - remove the difficulties or find an answer for
jump to conclusions - arrive too quickly at a decision or opinion
keep an eye on - watch closely
keep one’sfingers crossed - wish that nothing goes wrong
keep on one’s toes - be ready for action; prepared
knock oneself out - make a great effort
learn the ropes - learn the rules and routines of a place or activity