The three empires were- Ottoman, Safavid and Mughal empire.
The similarities were-
1- These originated as Turkic nomadic raiders of Central Asia based on military conquest.
2- These oriented to support armies & military classes using firearms.
3- They knew the effective use of firearms and siege warfare.
4- They were ruled by a disputed succession of absolute monarchs.
5- Tax policies conquered people heavily.
The differences were:
1- The ottomans spread over Anatolia Peninsula, Europe and North Africa. They had a zeal for Islamic conversion and mostly had Muslims and had a large Christian minority.The Muslims were Sunni Muslims.
2- The safavid spread over Persia ( now Iran).They had mostly shia Muslim.
3- The Mughals ruled predominantly non-Muslim population and spread over northern India. Mughals had different political tactics and social policies as compared to other two.