People talk a load of old tosh and piffle about Karma. It's not some sort of mystical spiritual form of natural justice, metered out by invisible ethereal spirits.
It is a very simple, down to earth and practical process, the mechanics of which are easy to follow.
If you treat people with love, respect, kindness and compassion, they will usually treat you the same way. If you are happy to lend a hand when someone needs your help, they are usually happy to reciprocate, when you are in trouble.
However if you are never there for people when they need you, you have no right to expect them to be there for you when you need them.
Simple and practical karmachanics. I always do what I can, to keep my karmic bank balance in credit, because you never know when you might need a good friend. Acts of kindness usually cost you little or nothing to give, but often bring great rewards.
