What are some specific things we can do to remove the love of the Dunya from our hearts and increase our spirituality besides avoiding Haram?
Bismillah
Thank you for your question. The heart is a battleground for two types of love. Love of God and love of the world. In order to remove the love of the world from the heart, the heart has to be filled with the love of God and this is the main purpose of self-purification and refinement and is the crux of spirituality in Islam. In one narration Imam al-Sadiq (as) says: "Is religion other than love."
It is achieved through battling the ego, with knowledge, faith and action. Through knowing the self and not succumbing to the desires of the lower self. By remaining patient in trials and tribulations and increasing one's hope and closeness to God. By realizing all of the ideals of Islam, its ethics and its practices.
May you always be successful