Robert told me of a wonderful lesson he learned about overcoming the “I can’t do it” mentality. When he was in his early 20’s, Robert had a terrible fear of heights. While working out in a local gym, he befriended some guys who worked at construction company that built skyscrapers in Manhattan. Because of his fear of heights, he asked one of these new friends, Jack, for help in overcoming his fear.
Jack agreed and told him to meet him at one of the construction sites so that he could take Robert to the top of a building and show him how to overcome his fear. Robert tried to talk him into telling him how to do it while they were still on the ground. Jack just laughed, and gave Robert directions to the building site.
Robert asked friends for prayer and gathering up his manly courage, after all these guys lifted weights together, the next Saturday he went to the building to meet Jack.  The two of them took construction elevator to the top. Robert describes what happened next.
Jack led me to the edge of a roof on the thirty-third floor. He told me to look down.  I was terrified.  My stomach was full of butterflies, I was dizzy, and my legs felt like putty. Then Jack told me to look across to another building. In other words, I was now looking out rather than down.  No problem.  No butterflies, no dizziness; I could that do just fine.  Then Jack said something that was so simple and so profound that I have never forgotten it and I use it in every area of my life: “Don’t look where you don’t want to go.”
When faced with a challenging situation, don’t think about what you don’t want to happen.  Don’t think about what you don’t want to say. Don’t think about what you don’t want to do; how you don’t want to look, or the result you don’t want. To lose the I can’t do it thinking, rather focus in on what you do want to do, or say, or have happen.

As Paul put it, Set your minds on things above, not on earthly things.  Colossians 3:2