Karma Yoga means doing your best work without getting attached to the outcome. One technique that is effective is to have the attitude that whatever you do is for God, and whatever result you get as what God gives you. Since you are doing everything for God, you will do your best in anything you do. The important thing is to take any outcome as God's gift to you (aka Prasada Buddhi).
How is this going to help you achieve materialistic goals?
It will, because you will be very good at your job. Everyone will be able to see the excellence of your work, and rewards will follow. Even if you don't ask for a raise or promotion, it will come to you, if not this year, the next year. We typically get disappointed if we don't get the reward right away. But in the long run, it doesn't matter that you got promoted a year later.
Reference: Bhagavad Gita Chapter 3
3.9 do your duty efficiently as a service or Seva to Me, free from attachment to the fruits of work
3.19 always perform your duty efficiently and without attachment to the results because by doing work without attachment one attains the Supreme
3.30 Dedicating all works to Me in a spiritual frame of mind, free from desire, attachment, and mental grief, do your duty.