Lowriderthug,
I must also mention that before you get into IEM systems, you have to be sure you can manage it well. It's not any simpler than managing wedges.
The best way to so this is to use the same type of IEM earbuds that the artist is using in order to know what he is hearing and in any case, what he asks to be louder and what to cut back, in short, you have to treat his IEM as an independent mix unlike the others. like with the bassy instruments like the Kick or the bass, you have to be able to make sure you don't put in so much that it would muddy up the whole mix. maybe even applying a Hi-pass filter to cut out a lot of the un-needed low end......anyway.......
2 things to make you perform better when doing monitors....
1) a controlled sound level on stage, work as a band, just turn up you amps for you to hear yourself, not the audience.......
2) a good pair of wedges, pay very particular attention to the vocal reproduction when choosing a wedge. not all 2-way wedges are created equal
3) if you are the guy doing the monitor mix, have a good pair of headphones....not those bassy DJ headphones!
4) keep the AUX at PRE-FADER
Hope this helps. There is a lot more to it but this will get you started.