Don Green of Grace Life Pulpit, gives us very practical instruction on how to mortify, kill the desire to be praised by men while doing works of righteousness. The issue of doing right things with wrong motivations concerns every believer. Pastor Green brings out two important points in his message on Matthew 6:1, In the Secret Place:

1. “Check your motives as you live the Christian life. He says, “Beware of practicing your righteousness.” It means that you turn your attention to this issue. He says, think about this with an air of caution. It is as though you are walking near the edge of the cliff that would plunge you to your death as you stepped over the line and He says, beware, there is danger here.”
2. “Choose your reward. Basically you have two choices that Jesus lays out here. He says you can choose the applause of men or you can choose the approval of God. You can’t have it both ways.

Excerpt: 

Why do you even care what people think? Their breath is in their nostrils. They are going to die and stand before God themselves. Getting their approval is meaningless compared to living for the blessing of God. So where this leads us is that as we recognize our spiritual duty from the Scriptures, we see that we want to seek the pleasure of God, the blessing of God, the approval of God, and whether men notice our good deeds or not is something that borders on irrelevance.

And so Jesus here on the Sermon on the Mount comes to you in the midst of everything that you do in the name of Christ and says, who are you trying to impress? Are you trying to impress the people who see you or are you seeking the smile of God? And the beauty of it, the glory of it is that on His infallible, impeccable word He says: God will greatly reward you when you seek His praise and His approval regardless of whether you gain the praise of men. It is all about what your highest heart aspiration is.

You can read the message here, or listen here.