It is a good sign that you feel deep remorse and sorrow for your misbehavior in the past. You should be glad to know that Allah is All-Forgiving and All-Merciful. He has promised forgiveness to all sinners, no matter how ugly their sins, once they have taken the necessary steps towards sincere repentance. The Prophet (peace and blessings be upon him) said:
“To feel remorse for one’s sin is a step towards repentance; and one who has repented of a sin is like someone who has never sinned at all!”
In your case it is simply enough for you to ask forgiveness of Allah and make a firm resolution in your mind never to repeat the same again, and promise yourself and Allah to stick with it.
doing the ablution well includes saying the Bismillah in the beginning, and some other prayer words after it such as:
"I bear witness that there is no deity save Allah , the one, and I also bear witness that Muhammad is his slave and messenger."
"O’ Allah! make me of the repenting, and make me of the purified."
"O’ Allah! with praises to you I bear witness that there is no deity but you. I seek your forgiveness and turn to you in repentance."
Offer two rak’ats of prayer. Performs them in full presence of mind and heart. Commits no mistake within the prayers. Does not speak to himself within them. Recites the prayer-words in them well and in humility. Then seeks Allah’s forgiveness.
