As of mental barriers, I believe hypnosis is an underestimated tool.
People are very different when it comes to susceptibility regarding hypnosis. I tried becoming hypnotised by one of the best in my country, and I was a hard nut, and he wouldn't be able to make me feel or see anything. But I noticed that I would allow my body to become hypnotised. You know, like: "Let your arm feel light and float like a balloon!", and the arm will obey and rise.
I have also hypnotised several people. It is very interesting and can work where other techniques may not seem so efficient.
I would try hypnosis it if I felt I had a mental barrier that kept me from something important.
Also self-hypnosis isn't really hard if first being susceptible to hypnosis in the first place. You may purchase a book or perhaps find a technique on the internet (if it is difficult to find a certified hypnotist in your area.)