A common question I am asked is, “With which instrument should I start mixing?”
Well I can think of at least four good answers to this, and possibly a fifth. I'll start with the drums and cover the other options over the course of this week.
If your song is intended to have real-sounding drums, perhaps real drums even, then they should sound like real drums being played in a real room, with a genuine-sounding room acoustic. The levels of all of the individual drum mics should therefore be in proportion. Since they will probably all be the same distance from their respective drum heads, then if the mics are identical it would be a good starting point to set them all at the same level (assuming that the preamp gains were all the same during the recording session). Balance the hihat mic against the snare, then bring up the overheads to balance the cymbals.
The kick drum however will need special attention. Since it is further from the overheads than anything else in the kit, it may sound a little dry. This might be acceptable to you, or you might add a little appropriate digital reverb.
It is often possible to get a realistic drum sound without EQ. If you do choose to EQ any particular drum however, make sure not to make it sound like it is from a different drum kit. Also, if you choose to compress any particular drum, consider whether you are making it too 'foreign' to the kit.
Work hard with the faders and pans to achieve a mix of the drums that genuinely does sound real. You can add reverb if you want to make the kit sound as though it is in a bigger room, but choose your reverb settings wisely.
Once you have this in place, buss the whole of the kit to a single stereo aux track. Now you can control the level of the whole kit with a single fader.
Electronic or sampled drums
If you have used electronic or sampled drums to create your rhythm track then the situation is a little bit different. If you don't want your drums to sound like real drums, or perhaps your samples are such that there is no possibility of that, then there is nothing 'real' to imitate.
In this case your task is to build up a convincing rhythm track before you start mixing in any other instruments or voices. Indeed, I would go further and say that you probably need to do this before you record any other instruments or voices.
When you are overdubbing instruments or voices to real drums, then even if your monitor mix isn't 100% realistic, then at least people know what the drums are supposed to sound like. But if you are constructing your rhythm track virtually from scratch, it needs to be a really good foundation for the music before you start adding to it.
In summary so far, if you start mixing with the drums or rhythm track, you should be able to achieve a solid foundation for your mix. This is an excellent point from which to start.