the guitars shouldn't phase if you EQ them properly and have different elements in each of the four tracks. listen to the guitar passage and make sure that ach of them build towards a strong song foundation by contributing different tones and elements. for example, have dueling guitars on 2 tracks, a rhythm on one, and maybe a drone type of guitar line on the last using an ebow or something that just surfaces every so often to add accents to a song passage. this way, you don't have too much going on at one time, helping the listener focus in on the "star"element of the guitar verse. also, back up the volume on the parts of the track that don't need to shine at a given time. if someone needs to sing somewhere, leave noodling out so you can help the drums and bass supplment the vocals a bit more. having a niche for other instruments is really important and will effectively help you avoid the "phasing" problem that most beginner mixers come across.
it should be important to know that the "phasing"you are referring to is not really phasing in the proper definition of the word. you just might happen to be playing the same verse during a passage, which makes a weird ghost sound at specific points of a song. this doubling is quite annoying. as such, EQ your guitar tracks according to the element you want to enhance: accent the highs for leads and add a bit of mids and bass to make it solid but strong; enhance the compression and EQ for rhythm guitars to make it chunky and solid, and smooth out the highs and lows on background guitar to make it less ovewhelming. design the riffs and leads to complement one another; back off on the rapid fire riffing if the song doesn't need it and use heavy chugging guitar liberly if you need a heavy groove to carry a song's energy further.
drums are hard to mix but you can easily get a good grasp of making good punchy drums by reading up on compression and reverb to add a TOUCH of dimension, warmth, and sonic strength. test the compression effect on your drums by toggling with the ratio. Ideally, the compression should breathe and let the dynamics of the player show through rather than choke his tracks to death. you can experiment with "ducking,"to add compression dynamically to drums by applying compression as a gate effects rather than as an insert on your recorder.
be careful about reverb and delay. this is a big problem with OPM commercial tracks that I sometimes can't understand. reverb and delay should only be added sparingly to give the guitars, vocals, or drums a bit of dimension if it otherwise sounds too sterile or solid. personally, i start with short decay reverbs and delay and work my way up from there depending on how the applied signal sits with the rest of the mix.
