Karma is the law of cause and effect. What you sow, so shall you reap. To minimize negative karma, don't do anything deemed negative even though you feel it is right - like killing roaches, ants or even mosquitoes. To maximize positive karma, do something good even though you don't want to do because of fear, anger or jealousy. Just be more aware of your thoughts, emotions, and actions. Then you would know whether it is generating negative or positive karma.
Cultivating Good Karma
The fastest way possible to cultivate good karma (or blessings) is to be aware of our surroundings. For example, don't walk carelessly and step on small insects, go out of your way to make someone smile or happy, especially the less fortunate (big blessings), or help elder people cross the road (big blessings). Additionally, cook for the underprivileged (big blessings) and show mercy to everyone and gratitude for all the lessons they bring whether by being hurtful, being cheated or getting scolded. Being in service of others is part of Dharma. In the time of Jesus, he said, if someone slaps you on the right cheek let him slap you on the left as well. Dharma was this challenging during His time.
The secret: Forget what goodness you have done as if it was part of your life just like breathing. Don't count or remember good deeds. Do you remember how many times you breathe in a day? Why, because it is simply a need and a natural process. If you don't breathe, suddenly you are aware, right? That is not natural. Earlier, I said we must be conscious of our surroundings. Being aware of our surroundings refers to the happenings around us. Later I said it is natural not to be aware of our breathing. Hence, I am talking about natural happenings that we do automatically. Please don't get confused with this two. Imagine our cultivation became so natural that we forgot whether it was hard, sweaty and time-consuming as if we have been doing this for many years. Even if you don't want to get the blessings, you will still receive it. Be aware of your super-ego. Sometimes you are not mindful of the fact that it has come out.
When you do something that does not require you to go out of the way, or so happens when you are there, the blessings are just mediocre. Those are considered small good deeds. We must always do small and big good deeds. What I have written in the beginning is seen as a substantial deed.