I need to understand the following points
1.) How database design ( Indexes and Locking Schemas) plays a role in blocking two processes.
2.) How long running transaction results into deadlocks.
3.) How Locking Schemas helps in avoiding deadlocks. (Read in manuals and online blogs )

Above all, How to solve Deadlock situation. Confused (moreover didn't understand below points)
1.) Acquire locks on objects in same order.
2.) Avoid use of holdlock.
3.) Use row-level locking instead of APL.

Thanks in advance for clearing my doubts.