There are a lot of common expressions that use in English language but the most common expressions are:
1-sleep on it يؤخرُ القرار لليوم التالي
e.x:I don't kill him today I will sleep on it.

2-take it easy خذ الأمور بسهولة
e.x.:Don't worry about your mistake take it easy

get the ball rolling=start-3
Get the ball rolling to demonstrate against the authority.