Everything you need to know is here:

Deadlocking

https://technet.microsoft.com/en-us/library/ms177433(v=sql.105).aspx

Detecting and Ending Deadlocks

https://technet.microsoft.com/en-us/library/ms178104(v=sql.105).aspx

Handling Deadlocks

https://technet.microsoft.com/en-us/library/ms177453(v=sql.105).aspx

Minimizing Deadlocks

https://technet.microsoft.com/en-us/library/ms191242(v=sql.105).aspx