The question I have for you is why is this person's approval so important to you. Clearly you need to do your job well to keep it, however if you are doing your job well then does it matter if this person praises you for it? If the only motivation for doing your job well is to get praise from your boss, then I think you have the wrong motivation. To succeed in being your best and giving your best in a job is to find something where the work itself is the reward. I love this saying and I have no idea who came up with it but it is so true, "Do what you love and you will never work a day in your life."
If you are more focused on the boss' opinion of your work than the work itself it may be time to look for another job, one that you love so that you can give your best and feel rewarded each day just by being there.