What is habit? Is it important? 

If we ask for a definition of habit, that will be "the compound interest of self-improvement." Habit is not a thing that will bring satisfying result in a short time. The most powerful outcomes are delayed. Success is the process of daily habits. If you do a work once in a while and think them as a habit - trust me that is not a habit.

Some people works hard and if they don't get their expecting outcomes they become impertinent about that work. But this should not be like this. Your work is never wasted. Maybe it is stored for your future success. Remember "Mastery requires patience."

This graph will help you to understand more easily.

If you can't reach to your goal you shouldn’t change your goal, you should change your way towards your goal. Inputs are depended on you but outputs are independent. Fix your inputs and outputs will fix themselves. 

Habit can work for you or against  you. So It's just like a double-edged sword. You need to be patient. Maybe everyday small changes won't  affect you much but it will show you a remarkable change in a long term way.

So best of luck with your goal. Just do your best and look how your goal comes to you.