When Jesus says things like "This is how they will know that you are my disciples, by your love for one another." and "Let your light so shine before men, that they may see your good deeds and praise your
Father in Heaven." he's saying that our Christian faith will be visible to those who are not Christians. But He also says "Beware of practicing your righteousness before men to be noticed by them, otherwise you have no reward with your Father in Heaven." So how do we know that we are doing "good works" versus "acts of righteousness". Jesus gave us the example of Salt and Light. Salt does stuff, but you don't actually SEE it doing it's stuff. Light illuminates everything, and cannot be hidden unless its covered up.
In this sermon Pastor Chris Kopp teaches on this subject. Delivered to the Galena Bible Church, Sunday April 6th, 2014.