When I was younger, I read a lot of self-help positive-thinking books. These books encouraged one to constantly think of their goals, and what they wanted to be. If a person wanted to sell so many products over a certain period of time, one needed to focus on those targets and visualize what was needed to be done to accomplish the goal.
What the writer of Colossians is encouraging the audience to do is somewhat similar. Our life and actions should reflect a focus of things connected to where Christ is now, versus things that are on earth. At times this can be very challenging when we have so many barriers in our society that can prevent us from doing this. That is why it is so important for those who want to do this to have a daily habit of prayer, Bible study, and reflection, which can aid in keeping ones focus on things above versus things on the earth. Vernon T.