Not many of you should presume to be teachers, my brothers, because you know that we who teach will be judged more strictly.
James has just finished discussing the role of works/deeds in our lives, and he is about to launch into a discussion of the tongue. In the middle there are a couple of verses that I don't think should be skimmed over. It is easy to move past these on your way to the verses on the tongue. It is also easy to pop in and take these verses without mentioning the context. So, trying not to ignore the context and trying not to skim past... let's take a look at these few verses.
In this verse it is stated that not many people should presume to be teachers. The reason that is given is that, if you teach, you will be judged more strictly. This isn't necessarily talking about God's judgment of you... It could be, but I believe it is referring to the obvious. When one teaches these things that James has been talking about, your life will be under scrutiny.
It is always true that you need to practice what you preach, but it may be more true if you are a teacher (or a preacher) that practicing what you preach becomes essential to your teaching.