1. Define your show goal. If you just want to do a show for practice so that your indie team can get some good reps in, then recognize that. You aren't trying to raise money, you aren't trying to get consistent packed houses (although that would be nice), you aren't even trying to build a reputation. You just want to practice. This is fine, and it is totally great.
If this is your goal, I recommend you stuff your show with as many groups as possible (up to 3 longform teams) and then charge the absolute minimum you can get away with (free if possible). This maximizes getting people to your show so you can have a fun time with your friends.
If your goal is to actually produce a real show, with consistent full houses, build a reputation, and maybe make some money (a very small amount), then recognize that at the core of all of this, you need a good product. You are now leaving pure artsy-land, and you are entering commercial land. Fundamentally the show (or product) you are selling, must be good. Otherwise, nobody will come see your show. This requires a lot of work, commitment, and a team effort. This is where Naffy lives.
2. Get a good team. I'm of the opinion that, like any performance art, it's all about talent. Not everybody can become a world class improviser, so be selective when creating a team. Don't just choose your friends. Choose people you'd love to be on stage with. Secondly, choose people who want to be on your team. If you have to convince them via arduous discussions/emails etc, just let it go. Tell them the overall team vision/show, and if they don't say yes immediately, get out of there.
Then, you need a coach/director. This is hard in small markets (not NYC, Chicago, LA), so I understand if this isn't an option. But if there's someone you like out there, ask him/her to coach you. I also recommend paying them. It forces them to be more professional and consistent. This is especially true if you are producing option 2 from above.
Lastly, you need to practice and get good. Give your team at least a month or two of just pure weekly practices before even trying a self-produced show. Fundamentally, your show has to be good and funny. If this is not true, then nothing else matters.
3. Marketing. I think this is where Naffy sets itself apart. There are a lot of talented indie teams out there. The difference? We go all out on marketing. Marketing is more complex than just making a facebook event and inviting friends. That's a nice starting point, but gets you zero non-friend audience. Here's the break down:
3a) Show time/price. This is a huge part. Recognize that Friday/Saturday nights are "prime time" and everything else is crap. So if you are on a crap day, your prices better insanely low (as in: FREE). If you are on a prime time slot, I recommend still staying cheap, probably around $5-$10, no more. What does Naffy do? We do both FREE and we are on a primetime night, thus we are maximizing audience as a tradeoff for money. But that's okay because none of us get paid anyway.
You also need regularity. The best is a weekly show, so you can just simply say "FRIDAYS AT 10PM" It's a lot easier than saying "FIRST THURSDAY OF THE MONTH" There's this thing of momentum with audience branding awareness, and if a show isn't weekly, it's hard to build momentum of the show. A monthly show might as well just be 12 isolated shows. Nobody will remember that the shows are even related. I know this is not easy to do, but I'm just telling you the best case scenario. We got lucky with Naffy that the Riot was open to us doing this, and we are very grateful to them. If you can't secure a weekly slot, then just take what you can get. But always have your eye open for that weekly spot.
3b) Show hook. Just naming your show after your team name is probably the absolutely worst idea for a show title. Nobody knows who you are and a flier that has your random improv team's name is complete garbage to the non-improvisor. What you need is some sort of a hook. Why would someone off the street be interested in seeing your show? What is it about? At the UCB they somewhat cracked this puzzle via interview shows, such as "Your Fucked Up Family", "What I Did for Love," "Shitty Jobs," and I think they had some about terrible roommates. Naffy basically does just this with our "Your Terrible Ex!" show. It's also the show that catapulted the Endgames improv theater. You need something catchy, easy to understand, and simple. I know it may sound gimmicky, but you have to do it.
3c) Fliers. Make good fliers. Don't just make something in word and do a screen capture. Browse other show fliers, copy things you like and what you didn't like. Spend a few hours learning drawing software from Youtube. I recommend Inkscape, it's free and awesome. I also recommend downloading cool fonts. There are a million cool fonts that are free. You can see the text in our fliers are all cool looking. I just used fonts that I found.
3d) Post Everywhere. Don't be lazy here. Post your flier, show hook, and a brief blurb on every event calendar you can find. And keep on doing this for each show that you have. Post on twitter, facebook, etc. Just go freakn' nuts.
Okay this was a really long post. Hopefully this will be a helpful starting point. There's a lot more, maybe I'll make a follow-up post, but this is just step 1. Good luck!