My sugestion to you would be to listen to the affect of each band as you cut and boost on a specific instrument.
A basic range of Frequency's is:
Highs - above 3.5 kHz
Mids - Between 250Hz and 3.5kHz
Lows - Below 250Hz
You can also break them into the following.
Brilliance - above 6kHz
Presence - above 3.5-6kHz
Upper mid's 1.5-3.5kHz
Lower mid's 250Hz-1.5kHz
Bass - 60Hz-250Hz
Sub bass below 60Hz
Dobro is right and it's really specific to your sound.
There are so many factors to your sound like room, mic, instrument. Also Eq is used as it's referenced to other sounds you are playing it with.
In very general terms - if your kickdrum is boosted in the 60Hz and 6kHz and cut at the 500Hz playing with that is your Bass guitar cut at 60Hz and 6kHz and boosted at 500Hz,
these 2 sounds have a better chance to work together becuase are independent and distinguishable as it minimizes the chance of one particular freq. being loaded.
I would take a sample of a kickdrum and play with it.
As you boost and cut discribe to yourself what changed.