Hi I am rated above 90% for Peak Master. I usually use one single type of reference like Drum Kit, since I believe the Drum kit covers a lot of Frequency spectrum and from stage to stage the reference sound does not change that much. In this way your ears can easily pick on the boosted frequency faster. Also I use the pink-noise practice button so you can get familiar with the boosted frequencies. The more you practice the narrower your translations will be. But don't get me wrong, as I get better at identifying frequency ranges I also practice with other references ike songs. guitars, synths etc. for the sake of applying this experience to the songs I mix or master.
I hope this helps.

@Roberto Mendoza: Thank you! It helping me. Now i get better rating than past and can pickup some frequency. May be it will improve more with practice.

I've found it most helpful to memorize some "keyframes". So find some frequency bands that you can easily identify and then listen for how each example deviates from those. For example, I've come up with the following keyframes in octave bands:
63 Hz = The really good deep, thumpy bass
125 Hz = The ugly bass that makes everything sound muddy
250 Hz = The good low-mid stuff. This is where the fundamental frequencies of most low notes happens.
500 Hz = This sounds like sound inside a box. Too much of it sounds really bad to me.
1000 Hz = This is the good mid-range stuff.
2000 Hz = This is the the high-mid stuff that makes be cringe
4000 Hz = Lots of good definition here. A lot of the clarity comes from here.
8000 Hz = This is where most of the sound of cymbals and such comes from
160000 Hz = This is the very subtle high stuff. Like the very edges of the cymbals.
So when I hear a frequency band boosted, I just try to figure out how close it is to one of these keyframes and then I guess.
Keep in mind that Peak Master uses 12 dB boosts in a pretty wide band. So a lot of frequencies (1/3 - 1/2 octave) are getting manipulated. You're trying to find the center frequency in that range.

The above tips are great. If you have access to an instrument (the piano is easiest for this) I've found it helpful to listen to certain notes and map frequencies to them to help orient myself on the frequency spectrum. Ex. A=440 corresponds to the A below middle C on a piano. And then the A below that is 220, and the A above it is 880. There's a chart of pitch to frequency mappings here: http://peabody.sapp.org/class/st2/lab/notehz/

@LJ Kadey, actually, the A below Middle C on a piano is 220. Ah, I see what you did: yes, the A directionally below Middle C (262 Hz) in the column 4 (looking vertically downward in column 4) is 440 - but is higher in pitch than Middle C. Below as far as pitch on a piano, it's the A to the left of the C in column 4, in column 3, A 220. But that''s just a chart reading mistake you made - no biggy.
Again, A below Middle C (262Hz) on a piano is 220, not 440.

Also note, (ignoring pitch and thinking only about note names) on a MIDI keyboard, depending on manufacturer, Middle C can be C3 or C4. For music theory, I believe Middle C is C4.

@John Miller You're correct! I should have written *ABOVE Middle C.

careful with c4 its highly explosive !
make yourself marks thats easier for you to remember and work work work !