The reason behind repentance should be the love of Allah The Almighty, glorifying Him, hoping for His reward and forgiveness and for fear of His punishment. Repentance should not be for the sake of coming close to a person and seeking a worldly gain behind it. Allah The Almighty Says (what means): {“Except those who repent (from hypocrisy), do righteous good deeds, hold fast to Allah, and purify their religion for Allah (by worshipping none but Allah, and do good for Allah’s sake only, not to show off), then they will be with the believers”}[Qur’an, 4: 146]
1. Refrain from sinning: Repentance is not considered genuine or accepted if a person continues to commit sins while in the process of repentance. On the other hand, committing the same sin after sincere repentance would not void the first repentance, but he will need to repent again.
2. Admitting to the sin: No one can repent from something he does not consider as a sin.
3. Regretting the sins: Repentance is sincere when a person regrets it and feels sad and grieved because of it; and it would not be accepted from the one who boasts about his sins. 
4. Determination not to repeat the sin again: Repentance would not be accepted from someone who intends to return to the same sin after his repentance; rather he should intend never to commit the sin again in the future.
5. According the people’s rights to them: If the sin is related to other people’s rights, then one must restore these rights to those from whom he usurped them, if he wants his repentance to be correct and accepted. 
6. Repenting during the time when it is accepted: Repentance is accepted before the moment of death and before the sun rises from the west. The Prophet, sallallaahu ‘alaihi wa sallam, said: “Allah spreads His Hand during the night (in a way which befits His Majesty) so that the sinners of the day would repent, and spreads His Hand during the day, so that the sinners of the night would repent, until the sun rises from the west.” [Muslim] and he, sallallaahu ‘alaihi wa sallam, also said: “No repentance is accepted at the moment of death.”[Ahmad, At-Tirmithi].

Signs of acceptance of repentance
* Becoming better than the condition you were in before repentance. 
* Continuously fearing returning to the same sin, because no one should feel safe while he does not know what Allah The Almighty has decreed for him; fear should accompany you until you hear the angels say, as Allah The Almighty Says (what means): {“Fear not, nor grieve! But receive the glad tidings of Paradise which you have been promised”}[Qur’an, 41: 30] only then fear and worry would disappear. 
* Feeling the magnitude of the sin or act of disobedience that he committed, even if you have repented for it. Ibn Mas’ood said: “As a result of his sin, a believer feels as though he is sitting under a mountain which he fears will fall on his head; but a sinner feels that his sins are just like a fly which landed on his nose and that he can simply drive it away by a simple move of his hand”. 
* Feeling humbleness and humility in your heart with your Lord; there is nothing dearer to Allah The Almighty than seeing His slave humbling and humiliating himself before Him; regretting and repenting; continuously mentioning Allah The Almighty. 
* Being aware of the actions of the limbs; you should guard your tongue from lying, backbiting, and tale-bearing, you should keep yourself busy with remembering and mentioning Allah The Almighty and reciting the Qur’an. You should guard your stomach from eating ill-gotten provision. You should guard your sight and not to look at prohibited things. You should guard your hearing and not to listen to music, lying or backbiting. You he should guard your hands and legs and not to use them in anything prohibited. You should guard your heart and not envy or hate anyone. You should guard your obedience and make it sincere and stay away from showing off and pride.
Article source: http://www.islamweb.net/emainpage/