How to increase my potential in daimoku? What if i cant chaant on a regular basis ? I want to increase my number of hours and i don't understand how to do it ?
Daimoku simply refers to the reciting of the title of the Heart Sutra. While this is a Tendai tradition, all Tendai monks would have been intimately familiar with the actual content of the Sutra. What you are asking is similar to "how can I get a better grade on my book report by just reading the cover?". 

The Heart Sutra states: there is no gain. Daimoku is a method, a vessel to get you to the other side. There's no point in finding a bigger boat as you won't be carrying it on your back once you reach the other side. Like you would leave the boat on the shore, Daimoku will just drop away. It's not a question of how much you recite, but of how.