I agree with your points where you say that a believer can develop his character by renewing his mind so that the enemy (Satan) does not gain access to his mind and begin to attack him against the right, he has as a believer.
Don’t make God’s word conform to your lifestyle, rather make your lifestyle conform to God’s word. “And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.’’ Romans 12:2
Now how we renew our minds is as follows;
a) Daily Prayer
b) Daily reading of the bible
c) Daily meditating on the word of God. “This book of the law shall not depart out from your mouth; but thou shalt meditate therein day and night, that mayest observe to do according to all that is written therein: for then thou shalt make thy way prosperous, and then thou shalt have good success.’’ Joshua 1:8
d) By choosing a godly character trait
e) Church Attendance; “Not forsaken the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.’’ Hebrew 10:25
The renewal of mind in a believer’s character makes him kingdom-minded and constant renewing of mind until Jesus comes helps mature the believer’s character in running this race.