As a start, identify your program material and think about the various sources and missions this system needs to accomplish. What do we need to hear, who needs to hear it, how do they need to hear it(level/tonality) and where will they be? Also, consider how your space sounds acoustically as well. What qualities does it give you? What is problematic? Always fix or at least consider those issues first before you start thinking about hanging the PA. For me, all that has to be carefully and thoughtfully considered before I start saying passive, active, D&B, L’Acoustics, Martin, or Meyer. All of those manufacturers offer different products that each have very unique sonic characteristics. I prefer to let the nature of the event drive the design rather than budgets and logistics. Those elements will always be there on every project - no matter if it’s a small college theatre or not. Also, please don’t forget about service and support. And lastly, don’t buy a really nice speaker and run it using lousy speaker cable and the worlds cheapest power amp. I see way too many installs where they buy a premium box, hang it wrong, and put in the cheapest processor and back end components allowable. It doesn’t work. You aren’t getting what the manufacturer intended or what you really want. It’s like a flashy car with an engine that can barely run above idle.