Be ambitious, keep climbing & always have hope. Beware of falling, & remember that life is minutes & seconds. Be like the ant in hard work, patience & perseverance. Always keep trying, & keep repenting. If you go back to sin, then repent again. Memorize Qur'an, & if you forget it, go back & memorize it again & again. The main thing is that you should never feel defeated or frustrated, because rationally speaking there's no such thing as the last word or the bitter end, rather there's always trial & error, & learning from your mistakes. Life is like a body that may undergo cosmetic surgery; it is like a building that can be renovated & rebuilt from scratch, with new decor & paint. Do away with all thoughts of failure, & stop thinking of calamities & problems, for Allah, the Almighty, says:

﴿ وَعَلَی اﷲِ فَتَوَكَّلُوٓا۠ اِن كُنتُم مُّومِنِينَ ٣٢۝ ﴾
( سورۃ المَاءده : ٢٣ )

{... and put your trust in Allah if you are indeed believers.}
(Qur'an 5: 23)

"Giving up sin is jihad (fighting in Allah's cause) , but persisting in it is stubbornness."