How can I discipline my mind

The art of thinning out your thoughts

In the rubber plantations, the planters thin out the rubber trees by cutting out the small excess trees that are next to the large trees. This enables them to obtain more milk (rubber sap) from the large trees. Likewise, thoughts must be thinned out, destroying one by one, in order to drink the ambrosia milk, the nectar of immortality.
Just as one keeps only the good fruits out of the basket and discards the bad ones, just as one keeps good thoughts in mind and discards the bad ones.
Just as the warrior chops off the enemies' heads one by one when they come out of the fortress through a trapdoor, so chop off the thoughts one by one when they emerge through the trapdoor to the surface of the mind.
When a lizard's tail is severed, the cut end will continue to move for a while because there is some residual prana left in the tail. After a minute or two, all movements stop. Likewise, when the thoughts are thinned out and their number smaller, some thoughts will continue to move, like the lizard's tail. But they are without power. They are unable to cause serious harm. There is no life force in them.
Just as the drowning person reaches for anything to save himself, so do these lifeless thoughts as well as they can to get back to their previous state of life and strength. If the daily practice of concentration and meditation is continued regularly, they will go out by themselves, like a lamp without ghee.
Passion, selfishness, jealousy, pride and hatred are very deeply rooted. If you cut off the branches of a tree, they will grow back after a while. Likewise, the thoughts that have been suppressed and thinned out reappear for a while after a while. They must be completely uprooted through strenuous effort, vichara, meditation, etc.