About EQ.... personally, I am pretty happy trusting the factory flat settings as the best jumping off place for a good recording. Only change it from there if you make a recording and it sounds bad.

Your biggest problem with EQ on globally is that, yes, a bit more sparkle might help your vocal, or brighten up a flat piano sound... But, at the same time, it turns your hi-hats into a nasty sibilant presence, makes your snare drum louder, all kinds of nasty things.

You are usually best served leaving the EQ off, and addressing each individual problem in isolation. If the piano needs brightening, do it on the piano part ONLY! If your vocal wants a hair more presence, do it on the vocal channel EQ (and don't forget, vocal presence EQ isn't up there in the 16kHz range!). But if you EQ the entire mix, you are usually creating as many problems as you are solving.

One last little trick I always do to a mix... Listen with the sound turned down VERY low! When you get your mix down that quiet, it is pretty easy to hear if one component is popping out too much, or getting lost. Turned up, you'll tend to be able to hear everything, but way down, and the balance becomes much more apparent.

Hope this helps.