We work from the theory that emotions are movements in the energy body that turn into physical feelings.
So firstly, notice where you are feeling the emotion in your body. Practice taking notice where the real feelings are - like with anger, it might be a flash that starts in your stomach and then moves up fast.
Put your hands where the most profound feelings can be felt (heat, pressure, trembling, pain), rub them round in a circle there, breathe deeply and think/say, "Soften and flow!"
Pay attention to what happens to the feelings, you want to get the energy to flow out somewhere to relieve the pressure.
Gets a lot easier with practice!