Here are some common idioms.
Break the ice
To break the ice is to do or say things that will make people who don’t know each other well feel relaxed.
On thin ice
When you are on thin ice, you are in a very tricky situation.
The icing on the cake
The icing on the cake is a special feature that makes something good even better.
Ill at ease
When you are ill at ease, you are uncomfortable or embarrassed.
The ins and outs
The ins and outs means all the details.
Initiate someone into
To initiate someone into something is to introduce them to a new activity.
Make inroads into
To make inroads is to make a gradual entry into something.
Insure someone against
To insure someone against something is to protect them against a possible event.
Iron something out
To iron something out is to settle a problem or difficulty.
Jump down someone’s throat
To jump down someone’s throat is to respond to someone in a sudden and angry way.
Jump the queue
To jump the queue is to move ahead of your proper place in a queue.
To jump ship is to leave a ship without permission.
One jump ahead
When you are one jump ahead, you are one stage ahead of your rival.