Fr. Chad Ripperger said some interesting things in this video on spiritual warfare, which I'll post below. But what really stood out to me was what he said about the tactics that Beelzebub likes to employ, they sound a lot like the key things I suffer from. Should I wage spiritual warfare against Beelzebub specifically? If so, are there any specific prayers or devotions I should know about and use?
I'd advise against singling out any demons specifically, just pray to Our Lady for purity. I also feel uncomfortable saying Beelzebub out loud (or lord of the flies, which is what it means)... Demons are like bullies, the best tactic is to ignore them and focus on something beautiful. Or give them a good wallop on the nose by saying a Hail Mary
Yes focus on the positive. St Teresa of Avila's father one time was going to do a Retreat and hetold her he was going to meditate on hell. She adivsed him not to for the same reason.
St. Aloysius is a great saint for interceding on our behalf for purity. Try to find a prayer online and print it out and say it every day.