What are some ways to improve my practice?

I meditate for 30 minutes each day, focusing on the feeling of my breath moving through my throat. When I am not meditating, I try to mentally "say" whatever it is I am doing (e.g. if I am angry, I say "angry" in my head). I also adhere to the five precepts. I have been following this routine for about six months now, and at this point I feel like I am seeing fewer results than ever before. I often am unable to maintain focus for the full 30 minutes or even a substantial part of the meditation time; I still find myself becoming irrationally angry towards people...it is discouraging. How can I augment or change my practice to find peace and be less angry? Thx!