Personal growth is a partnership

And may the Lord our God show us his approval and make our efforts successful. Yes, make our efforts successful! (Psalm 90:17 NLT)

 You expect God to work an overnight wonder in you, with nothing required of you beyond wanting and praying to do better. That’s not the way it works. God will do for you what only He can do, but He also expects you to do what you can. It takes both. Personal growth is a partnership.
God heard your prayer and brought the desired answer into the realm of possibility the instant you prayed, but now it is up to you to put the answer into effect and make it a reality. You need to start acting changed, even if you don’t feel changed.
 If you prayed to be less negative and critical of others, for example, you need to make an effort to be positive and see the good in others. God will inspire positive thoughts and help you catch yourself when you begin to become negative or critical, but then you have to follow His lead and deliberately choose the good and reject the bad. Desiring to change and praying for that was the right choice, but now you need to make that choice over and over until it becomes second nature.
 Inner change is a process that takes commitment, time, effort, and patience, but it is one of the most rewarding experiences in life. [1]

 There are some people who live in a dream world, and there are some who face reality; and then there are those who turn one into the other.—Douglas H. Everett (1916–2002

[1] Activated How Inner Change Works