How can a Muslim who does not feel faith and comfort in his life, but regrets wasting prayers and wishes to do what pleases Allah to enter Paradise with the Prophet, peace and blessings be upon him, begin to strengthen his faith and perform good deeds?

Feelings of shortcoming and the desire for self-purification are good motives, but they should not lead to frustration, but rather to action. Seek refuge in Allah from helplessness and laziness, and be keen on what benefits you. Fear Allah as He should be feared, and remember His promise and His warning. Increase your remembrance of Allah, for in it is tranquility for the heart. Seek forgiveness from Allah for what you have neglected of His commands, for Allah extends His hand by night and day for repentance, and forgives sins no matter how great they are. Start with the obligatory duties and refraining from forbidden acts, then gradually move to the recommended acts. Beware of procrastination, hasten to acts of obedience, and persist in good deeds even if they are few.