Karma means action. Every action triggers a sequence of consequences. Positive actions yield positive consequences while negative actions do the opposite. Positive and negative consequences can cancel out each other. The concept of karma includes the consequences of one's action.
The Bhagavad Gita teaches that there are 3 kinds of karma - sanchita which is the entire karmic baggage, prarabdha which is the karmic baggage allocated for the current lifetime and kriyamana which is fresh karmic baggage being added on.
From the upanishads, one learns that there are 4 paths of yoga to help in dealing with karma - bhakthi, karma, njana and kriya. This is dealt with in more detail here. The popular mainstream religions offer bhakthi (devotion) and karma (service) as essential elements of piety. The advaita practices offer intellectual pursuit and meditative inward seeking as mechanisms to deal with karma.
We each have to search for the path that works best for us. This is usually defined by the religious heritage of the individual. Those who are not satisfied with the teachings offered by their religious tradition go in search of answers. Seekers from various disciplines very often find themselves headed in a common direction. That is because all traditions come from the same source.
May you find the path that works well for you.
