Yet another yo-ji that highly appeals to the part of me that wishes I was まじめ, or even えらい.
率先 means taking the initiative: 人の先に立つこと. 先 is usually among the first kanji that most people learn, so I'll leave that alone and just say that 率 is a very, very useful kanji to know, because you can attach it to almost anything to make "the ______ rate:" like 出産率, 死亡率, 失業率 or 換算率. It gets used a lot in relation to percentages (出席率), proportion (倍率), and it's even one of the cornerstones of the word for probability: 確率. Plus, tiny bit of trivia, it's in the Japanese name for pi: 円周率.
垂範 means setting an example, and I'm not sure exactly why. If anyone knows how the first kanji comes into play, please comment away!
Back to 率先垂範.
1. To lead by example.
Personally, I like to think of this one in conjunction with 不言実行, and in opposition to 反面教師.
Very, very common yo-ji for use in business situations.
Japan's Business Leaders Don't Meet the Global Standard: A Change from the "Good Example" Model of Employee Training to Guided Development will be Indispensable. (trans. Nirav)