Well said Axeslash !
From my personal experience:
1. The guitar is meant to sit in the medium frequencies. While it's nice and fancy when you are alone to get a bassy, and mid scooped sound, it just doesn't work in the band context. So... keep that in mind when voicing your guitar tone
2. You just wont be able to rely on the FOH guy at everyshow, especially in small places. Learn how to sound good without the help of the PA, IE use a cab that you can use as your personal monitor or even as the main source of your sound when playing in small places. And of course, your direct sound should sound good too (find a way to profile your sound through your regular speaker that you can send to the PA, if you can)
3. that also implies... at some rehearsals, find the time to test/check the sound of the whole band (record it if possible). a FOH engineer, as good as he/she can be, cannot transform a bad sound... Garbage in, garbage out, so make your sound the best possible before hitting the stage, and learn how to get the best sound in any places you will play.