One can easily waste a lot of time trying to still mind with long hours of meditation when one is not living a lifestyle that is supportive of meditation.
You see, food and substances have a huge influence on our mind-states, much stronger than many are aware of.
If one habitually consumes things like alcohol, cigarettes, too much coffee, and highly palatable foods, like (processed) foods rich in sugar, salt, fat and flavorings, it will cause the mind to be dopamine addicted, and therefore to be in an almost constant state of slight dissatisfaction, always seeking for the next moment of pleasure.
This will in turn cause the mind to be over-active, imbalanced, and jumpy, and it will make your efforts to meditate and concentrate so much more strenuous.
Where on the contrary, if you’re not bound by too many strong addictions, and your diet is sattvic, light and healthy, and low in overly stimulating foods, you’ve already done half of the work.
Your mind will effortlessly be more silent and present, meditation arises more naturally, and you will more easily be able to let go of the ego trying to pull you left and right.