Shaykh Zulfiqar Ahmad Naqshbandi (DB) in his book “Dua- The Essence of Worship” shares a deep secret with his readers- A Secret for the acceptance of Dua. He says in his book: Some say: Hazrat we make a lot of dua’s but it is not accepted, students many times say that they are in difficulties, even the ulama’s and scholars request for dua’s. He says: I will teach my friends a secret for the acceptance of dua’s. If you practice upon it, InshaAllah, you will no longer need to search of the Isme Azam. You will see it before your eyes your dua’s being accepted just as you complete it. I have experienced this not a hundred times but a thousand times. The action is small but the results are great. The secret for the acceptance of dua’s that the author has learnt from his elders and that he has experienced thousands of times is:

Whenever a time comes in your life when you have the opportunity to commit a sin and you refrain due to fear of Allah, at that very moment, make a dua to Allah and Allah will InshaAllah, accept your dua at that very moment.

After one has refrained from a particular sin, any dua done with full faith, full trust and full humility comming from the depths of the heart should suffice for acceptance, however, we would like to share a simple general format of making dua, which InshaAllah, will complement your dua’s

Source: https://islambestreligion.wordpress.com/2011/10/11/a-secret-for-the-acceptance-of-dua/