How to avoid Deadlocks...

Hi,

I have two tables, table A and B.Table A is Master table and table B is child table.They are having foreign key between them.

There is Application X which updates/insertes in thse tables.
And there is Application Y which uses joins with table A, B and other tables and uses the data.

Now I am getting deadlocks and timeout in Application X and Y both.

How can I remove the deadlocks and timeout in the above case and both Application X and Y can use the tables effectively.