Stopping porn and mastrubation

Dear all,

I started masturbation and watching porn when I was 12 years old. Every time I watched porn I felt ashamed for myself, family, girlfriends, and friends. When I was in a difficult situation I always felt back into this bad habit. I tried many times to quit watching porn but every time I failed. The amount of watching porn has decreased but the urge and addiction has never gone away. I never tried to stop porn AND masturbation, maybe this decision will help me to finally get rid of this addiction.

Does anyone have tips & tricks for me to quit this addiction? And when do you notice positive effects? I am very determined to achieve the 90 days goal.