The Principles of Karma Yoga can be summed up in simple words. They are as follows;
It’s not what you do that matter, as much as your attitude while performing the task that determines whether it is Karma Yoga, i.e.
liberating, or binding.
Work is worship and the philosophy of Karma Yoga exhorts you to "give your hands to work, and keep your mind fixed on the Supreme goal."
Just like attitude, it is not what you do that matters as much as the real motive behind it. One’s motive ought to be pure. Normally, people plans for the fruits of their works long before they start any work. Our minds are framed in such a manner that they cannot conceive of any kind of work without remuneration or reward. Karma Yoga postulates that Selfless Service is the only way to happiness.
Oftentimes "duty" is called righteousness; this is in Oriental scriptures. It means incurring demerit by shunning one’s duty. Our duty is towards the true Self, or the Inner Guru who teaches us through all the circumstances of life just the way they appear.
Whatever one has to do, one ought to do one’s best. If you become aware of another, better way to serve, one ought to use it, promptly. Never hesitate or delay just through fear of effort or fear of criticism. Never work sloppily just when no one is observing or because you don’t feel up to the work at hand.
All tasks are teachers of some sort. People are able to learn different skills just by performing different tasks. All jobs have different requirements by way of time, degree of focus, skills or experience. Lie wise, different jobs call for different emotional input, physical energy, will power, so on and so forth; so you must try to do whatever you are doing, well.