I'm in my fourth year of teaching in a lovely school and generally really enjoy my job. However, I'm a still struggling with managing the behaviour in some classes - generally year 9/10 classes with a large number of decent but loud/challenging pupils. I can manage the really bad behaviour but it's when I have a big group of pupils who are all loud and a bit rude or just easily distracted. I'm getting better but very slowly and it seems to take me ages to win them over and actually get them on side. My current year 10s have no respect atm and I struggle to be strict enough/manage behaviour without feeling that I am just constantly moaning and being negative. They don't take me very seriously. We have some great lessons then some awful ones. The pupils are (almost) all really nice individually but turn in to a rowdy mob when they are together.
My HOD has observed me and just said to carry on but it's something I'd really like to work on. I don't know where to start though as I'm not completely sure where I am going wrong. Can anyone recommend any training courses/CPD that might help? Any tips or suggestions?