I referee U16's-17s quite often and am only a few years older myself so understand the challenge it can pose. However, before the game I make a point of telling the captain at the toss up what the boundaries are in terms of dissent etc and what won't be tolerated. Then I emphasise to the captain that they need to go straight back to their huddle/team and tell his teammates and their manager what I have just said as I don't want anybody complaining that they didn't know what I expect of them.Thanks for the replies everyone, The age group I Referee is u16's, I am only a few years older than them so it's a bit of a challenge for me, sometimes I feel like they take this for granted and that they can get away with shouting things etc because I'm a young referee, and to answer the first question I referee them every week as I'm friendly with their manager and have agreed to referee all their home games this season. Thanks for the advice in all the replies, I also referee u12's and Never have any problems, maybe once or twice. U16's is certainly my biggest challenge so far!
I'm sure there are better ways than this such as having a word with the team as a whole before the game but this approach has worked for me so far. Since I've started using this approach, cautions for dissent have dropped and the ones I have given, are viewed with more understanding by club officials.
Hope this helps and don't let that one player ruin your game !