Informal groups that pick up garbage and plant flowers on an irregular basis can do a very good job of beautifying the park without ever even giving themselves a name. However, if your group has larger goals, like renovating the playground or combating crime, you're going to need more structure. Structure is also important for mid-sized goals like hosting a festival because you need a formal structure in order to raise money.
What Is Structure?
Structure is what makes you a formal organization. It consists of:
A Name and a Logo -- a name makes your group official. It looks great on flyers and in newspaper articles and on top of your letterhead. At the risk of pointing out the obvious, remember that having a name gives you a way to get credit for what you do.
Regular Meetings -- both so group leaders can check in with each other and can report back to the general membership and ask for their input. Meetings keep your organization from turning into a one-person show.
Elected Leadership -- though the general membership usually vote for the "natural leaders" anyway, elections mean that your group is democratic, that one person isn't calling all the shots. Regular elections also mean that a leader can pass on the torch before he or she burns out.
Committees -- a great way to delegate responsibility and find new leaders. By spreading out the work, responsibility, and credit among many people, committees let you get a lot more done.
Regular Communications -- as your group gets bigger, you'll need a way to make the general membership feel like they're in the loop. Even if they only come out once or twice a year, newsletters and bulletins are an important tool for holding on to your membership. They're also good for sending to people you want to impress.
Legal Stuff -- there are many government forms that help you deal with liability and financial issues. Though these may seem like a hassle, they protect you and let you raise more money than you could otherwise.
Money Stuff -- a bank account, a budget, "the books," tax returns...
Official Memberships -- by officially recognizing members and letting them know that they are members, you create a support group -- people you can ask to volunteer, people you can send mailings to, people you can ask for money, people you can call "members" when you're asking someone else for money and trying to look big and well-organized.
Records -- files filled with letters you've written and received, and newspaper articles, and old flyers, and photographs, and legal documents, and membership lists, and business cards. If your group is to continue to exist through the years as leadership changes you must have a way of passing on important information.