I won’t touch the topic of live sound reinforcement very often on this site. I have not worked in that capacity enough to speak on the subject. But, I will recommend a few resources in case that is one direction that you as a music production business entrepreneur want to head.
First, this book is the one I would recommend to buy first. It is filled with practical knowledge and is suited for both new and advanced engineers alike. Simply put, the author Bill Evans is the man!
Second, the Live Sound section of Gearslutz is a great resource. As a whole that place can be a little off the walls but the Live Sound section has a lot of smart men and women talking shop and answering questions.
Third, Rational Acoustics Smaart. I only bring this up because a few years back a colleague could not stop talking about it. If you have read my article about speaker calibration, you know that I’m all about using new technology to solve every day problems that audio engineers face. Smaart is the Sonarworks Reference for live sound. While both software products aren’t necessary, they do make your job a hell of a lot easier.
Fourth, the Radial JDX 48 Reactor or the Rivera Mini RockRec Loadbox. These two products can make live guitar amplification easier. The less stage bleed the better. Another great product is the Two Notes Torpedo Reload but it is on the expensive side. There’s also this but its impedance is fixed. Which means it isn’t very versatile.
Fifth, get supercardiod microphones. You’ll thank me later.
Sixth, if a recording of the live show is needed then so is a separate feed from the mix. An engineer to man that feed is also necessary. That’s what Radial OX8 splitters were designed for.
Seventh, ground stacked subwoofers suck. Fly them like you do the main speakers and use a digital crossover so they gel together nicely.
Eighth, you’ll learn this soon enough with experience. Sound check is one thing but when you add an audience to the room acoustics change the way things sound.
That about covers it for now. Again, buy that Bill Evans book either digitally or in paperback. It is like having a seasoned professional mentor tell you nearly everything that you need to know.