Find a Venue: This is the important one, because without a venue, there is no show. This can be as simple as a garage, basement, pole barn, field-anything with power and room for a band. It also doesn't hurt if you can avoid getting noise complaints, so sound proofed or somewhat isolated are important factors.
Find a Backup Venue: It's only a matter of time before you run into venue problems, so why not be prepared? Sometimes a venue will close for repairs or financial reasons. Sometimes they will get cold feet. Sometimes you don't have enough money for a deposit, so make sure you have a backup plan. There's nothing worse than having the bands booked only to find out that you don't have a place for them to play.
Book a Headlining Band: You may want to start small with some local bands to get a feel for the process and pitfalls before you invite a touring band to play. Pick the band you think will have the biggest draw. Sometimes this doesn't necessarily mean they will be a good band, but they may have lots of friends or fans. The key is to get a good turnout. Remember, touring bands are often sleeping on floors, living on crap food and playing to small, unforgiving crowds, so think about how to entice them. Offer them a place to sleep, a nice, home-cooked meal and work your tail off to get them a good crowd. Also ask them how much they need to make for gas and expenses. And if you are cooking or providing food, make sure you know if they are vegetarians, vegans or omnivores. Some bands will want a guarantee, meaning they need to make x amount of dollars each show. Your best bet, if you are a small promoter, is to avoid such bands. Avoid contracts. Just promise you will work hard for them and deliver.
Book Opening Bands: Most DIY shows have from 3-5 bands play. I think 5 is way too many, and 4 is pushing it, myself. Opening bands are important, and I suggest you look for local bands with a good fanbase for your middle opening band. The first opening band can easily be a new band, or your band. They should play the shortest set. The middle band should be a big local draw. If the touring band has a supporting act with them, even better. Sometimes, the touring band will need to leave early to get to their next destination, so you may have to put a local band as the headliner. Unless the touring band asks, never put them on first. And a good secret: the middle slot is usually the best slot. People tend to show up late and leave early.
Get Organized: Plan out a budget. Target how many people you need to attend to break even. Determine your cover charge for people to get in. Buy a hand stamp so you know who has paid. Figure out how much the headliner needs to be paid, then allocate a little for the opening bands. Also make sure to budget in some profit for yourself after covering your expenses (flyers, phone bills, etc.). The profit can go towards your next show. Also decide how many people each band can have on their guest list and make sure they turn in their guest lists before the doors open. You will probably have to chase a band member down before the show to get this info.
Confirm Everyone: One week or less before the show, make sure you confirm all of the bands AND the venue. Be organized, telling them when they are going on, what they need to bring (i.e., do you have a PA system, or do they need to bring one? Will you have a Merch table so they can sell stuff?), and what the venue is like. Some bands are particular about stage setups, so make sure there are no surprises. This way, if someone is flaking, you will find out in time to replace them.
Promote, Promote, Promote: I cannot stress the importance of this step more. You need to get the word out. You can't rely on word-of-mouth, and it is your job to make sure people are there to see the show. I can't tell you how disappointing and disheartening it is to be a touring band, drive miles and miles and miles in a hot, smelly van, starving, to play a show to three people in the middle of nowhere. Print up flyers, plaster them everywhere. Get your friends helping out. Talk to people. Make them promise to attend. Use the Internets. E-Mail people. Start a MySpace page for your shows. Anything! And don't rule out non-punk people. Where I grew up, we often got all kinds of people to show up, because it was live music. In some cases, people even discovered a favorite new genre or band.
Plan the Event: Get some help here-get someone to help get stuff for the bands. Get someone to watch the door and take money. Make sure you have some cash for change. Get someone to run the P.A. Come up with security contingencies: How will you deal with unruly kids (and there will be some)? Get everyone to be on their best behavior by explaining that you can keep doing shows as long as nobody messes them up. I also strongly advise you bar drugs or alcohol. If you should get reported for noise violations, that will only make things worse. People can have fun without those when music is involved. Also damage protect the venue, especially if it's your house. Hide valuables, protect fragile items. People will go off and that's to be expected, but be prepared.
Put on the Show: If you've done your homework, everything should go well with little bumps. But be prepared for the unexpected and deal with it calmly and logically. If you are renting a space, the owners will be impressed by your professionalism and won't be dubious about putting on future shows. Make sure, also, to clean up the venue when you are done, leaving it like you found it. Often, rental venues will require a security deposit and you don't want to lose that to laziness.
Most of all, have fun. Putting on a good show is stressful, time consuming and somewhat crazy. But it's also very rewarding. Now go forth and conquer the legions of rock!