Daniel chose to eat only vegetables (beans) and water, instead of the meat and wine the king offered. Note that this passage is not saying you should never eat meat or drink alcohol. However, our body is a temple wherein dwelleth the Holy Spirit and we need to take good care of our health.
Daniel could have compromised. "Daniel, just eat the king's food, and you'll have more favour with the king and get to influence him more that way." This is the attitude of most people in the church today.
Daniel was faithful in his beliefs regarding the kinds of food the king ate and it turned out well for him and the three other young men in the end. May we always do the right thing and always be faithful.
Daniel was also very bold. We need to remember the four Hebrew children were prisoners. It wasn't as if they were guests who had some say in what they wanted to do during their stay. Therefore, Daniel was very bold to ask the servant to only serve the four of them pulses and water. May we be bold like him.