How can one increase love for Allah in their heart? I have been struggling to stop a sin for a long time with little success and I think if I have great love for Allah then I will not desire to sin.

To increase your love for Allah, you need the following:

1. Hang around with friends who are God fearing and are able to remind you of your divine duties
2. Pledge between you and Allah that if you ever commit a sin, you will do an act of worship or a charity for the sake of Allah. Say for example, if I sin, I will feed 10 orphans or pray Namaz shab for 40 days etc
3. Do your daily prayers regularly without fail. Make sure your daily prayers are on time
4. Make the Holy Qur’an your friend by committing to read and reflect at least few verses daily