Layer your lead guitar tracks multiple times. As a guitar-driven genre, heavy metal requires a great deal of emphasis on its lead guitars. For the fullest sound possible, take multiple recordings of the same riff and layer it three to four times, panned in each channel to create an intense, surrounding effect. For example, pan one track 50% to the left, and another 50% to the right. Then pan your third track 25% to the left, and the fourth 25% to the right. Do this for each lead guitar riff.
Create a drum presence. The beat drives the melody and gives heavy metal music its energy, so make sure that your percussion does not take a backseat but stands out boldly. Add a small amount of compression to your drum tracks using a multiband compressor and raise the amount of attack. You can also add punch to your drums by slightly increasing the amount of post gain on your compressor.
Layer your vocals and add reverb. The aggressive instrumentation of heavy metal music can easily drown out a voice, and too much volume in a vocal track will make the singing stand above the mix and sound unnatural. By duplicating your vocal recordings and placing them on top of one another in two separate vocal tracks, you provide the voice with additional presence in the mix. Finally, add a very small amount of reverb to your vocal tracks in order to help the vocals blend into the mix.
Pan your rhythm guitar. While the lead guitars should surround you, the rhythm guitars should be panned approximately 25 to 65 percent to the left or right. Much as musicians stand at different parts of a stage, you want your mix to sound three-dimensional, and not overly centralized.