Why out of all the Europeans only the British succeeded in establishing an empire in India?

The British were successful in carving out an empire in India due to the following reasons:

• Superior navy technology
• Advancements in military technology 
• Deft political maneuvering along with military actions managed to subdue local kingdoms against insurmountable odds

For further reading check the following articles:

• British Empire
• British Raj
• European Colonialism