It’s important understand that Rav Hool is literally ‘going to war’ on your behalf to destroy the Ayin Horah. Rav Hool feels that the Siyyatah Dishmayah (Heavenly help) he has in successfully helping people is because he insists on a ‘Kabolas Mitzvah’.
This means that the person who has the procedure done for them (or the person ordering it on their behalf) should undertake to strengthen themselves in a Mitzvah of their choice. They do not need to tell Rav Hool what their Kaboloh is.
Now, this is not a verbal promise, or ‘Neder’, and you don’t need to worry if you miss doing it a few times – Rav Hool just needs your wholehearted intention to keep it when he does the procedure for you. In fact, that’s why he asks you to consider something small and manageable. It could be saying a Brochoh with extra concentration, being particular to recite ‘Modeh Ani’ each morning, or increasing in Torah study and so on. It needs to be a genuinely sincere undertaking, therefore it needs to be manageable and within your reach. Rav Hool once told a non-religious couple, “There is a Halochoh that you should put on your right shoe before your left. I ask you to be particular to do this from now”.
Some people have undertaken to increase in their Kavonoh each day when putting on their Talis and reciting the Brochoh. Others have resolved to saying the 23rd chapter of Tehilim, “Mizmor le’Dovid, Hashem Ro’ey” during a meal - this takes twenty seconds to recite, elevates a mundane meal to a holy one, and is also Segulah for Parnosoh.
Some people who perform the procedure for removing Ayin Horah do not require the person they are helping to do anything. However, Rav Hool feels that the ‘Kabolas Mitzvah’, undertaking an improvement in performing Mitzvos, is a holy partnership that is integral to the procedure’s success. He only agrees to do the procedure if a ‘Kabolas Mitzvah’ is made.