Answering these questions may help you write a sharper testimony with more concrete details.

Before you received Christ
How you received Christ
After you received Christ
Favourite Verse

Before I received Christ, I lived and thought this way 

What were your attitudes, needs, problems, world view?

What did your life revolve around?  What was most important to you?

How did you look for security, peace of mind, happiness? What was your small god?

How did you find your activities unsatisfying?

How I received Christ  

When did you first hear the gospel? How? Or, when were you first exposed to dynamic Christianity?

What were your initial reactions to Jesus Christ?

When and why did you begin to feel positive about Christianity?

What was the turning point in your attitude?

What mental barriers did you face?

How did you pray to receive Christ?  What was your prayer?

After I received Christ, these changes took place  

What changes did you see in your life, actions, attitudes, problems (use specific examples).

How long did it take before you noticed changes (be honest and realistic)?

Pertinent or Favourite Verse : 

What Bible verse do you think would challenge your hearers the most?

What Bible verse has helped you the most in life?

Please don't give the reference when speaking (most non-Christians do not know what a "Deuteronomy" is).  You can introduce the quote with "The Bible says" or "Jesus said ".