Block parties, fueled by sunshine and new neighbors, can be fun to attend. And gathering 15 to 100 familiar and unfamiliar faces can be satisfying, a reward that goes beyond the goal of strengthening a community.

"It's seeing all those smiling faces," said Rita Walters, a resident of Baltimore who organizes backyard parties for up to 20 guests with her neighbor. "We share a lawn, get along well and enjoy the fun of putting people together.

"Small parties are more personal. You can get to know people, and decisions made by two people are easier than doing it by committee. We just pick a date, assign a dish to each household, then ask for a donation [$5 for singles; $10 for families] for beverages, which we buy."

Patricia Widmayer sharpened skills for organizing neighborhood parties while raising a family in Evanston, Ill. There were backyard potlucks for 18, and bigger parties that required street closings.

"Remember, the goal is to introduce people and strengthen the community," said Widmayer, an education consultant in Chicago.

The size of the party will determine how extensive the planning needs to be and how duties are delegated. Some parties are successful with two organizers. Others require committees, volunteers and city permits. A novice organizer needs to be realistic.

"Ask for help, and pick someone you can work with," advised Sandi Smith, an events coordinator from Ocean City, Md. "Anticipate problems and solutions. Innovate."

The following advice comes from veteran volunteer organizers and professional event planners around the country:

Size and scope: Consider how many people you can realistically host. Closing down a street to accommodate 20 households is more challenging and time-consuming than organizing a backyard bash for four families. Two couples can easily organize a party for 25, said Widmayer. Decisions are easier to make among four people — but understand that there's always an unexpected expense or two at the last minute that is absorbed, quietly, by the hosts, she said.

Timeline: Bigger parties (50 or more) require forward planning. Once the date, venue and type of party are agreed upon, the date needs to be reconfirmed with local community calendars to avoid conflicts. Sending a "save the date" e-mail or postcard to guests two months in advance is suggested. Try to provide as much information as you can, including date, time (beginning and ending), location, purpose, what to bring (and/or how much to pay or donate). Include contact information plus a deadline for RSVPs.

Policies, permits: Allow enough time to apply for and comply with a city's application requirements to hold a special event on public property (closing a street, say, or redirecting traffic). Permits will be required if the event involves a public park, alcohol consumption and sound-amplifying equipment. Policies vary by municipality; be sure everyone understands, and follows, all of the ordinances.

Familiarize yourself with local noise ordinances as they apply to sound equipment, and understand the meaning of "unreasonable noise." Make sure musicians and DJs understand the rules and will be responsible for equipment setup and technical know-how.

RSVPs: Enforce a deadline for RSVPs. Obtaining a head count determines how much food and beverages you'll need, and can affect the size of a discount when buying food in bulk, said Martha Marani, who organized an annual neighborhood crab boil every Labor Day in Baltimore for nearly 10 years.

Corralling help: For larger events, tap into community service-minded groups such as banks, law firms, hospitals, corporations. "They often encourage employees to participate in community events," said Smith. "Volunteer groups of nurses, paramedics and EMS personnel will participate if given advance notice — same with [firefighters] who often arrive with the firetruck, which kids love."

Be mindful of volunteers' time: In devising work shifts for a larger event, create a few time slots that require short commitments, said Cyndi Allen, a veteran organizer for the annual picnic of the Hartland Homeowners Association in Lexington, Ky. "Donating two hours is more realistic for some people than six. Minimize the 'don't show' rate by adjusting numbers," Allen says. "Always err on having too many volunteers or too much food."

Rentals: Need a tent, tables and chairs, a grill or volleyball net? Borrow from schools or churches. Or get personal recommendations on rental companies, then eyeball all items in person, said Debie Pageau, a Tucson-based professional event organizer. Before you sign a contract, read the fine print (or enlist legal expertise). Make time to inspect each piece of rental equipment — its condition, the numbers — upon delivery. Always confirm availability of on-site technical assistance or after-hours phone contact for live help. And regarding another kind of rental …

Sanitation matters: For large groups, negotiate for rental portable toilets. For smaller events, encourage families to use their own homes. If individual homeowners volunteer their bathrooms, be sure each has a security measure in place if the home is unattended.

Contingency plan: It pays to collect "plan Bs." Smith recalled the time a DJ, hired to provide tunes and a sound system for a post-triathlon party, overslept. Her crew borrowed a megaphone from a state trooper, then tapped a guest who offered to crank up his new car radio.

Weather watch: Because weather is unpredictable, Pageau prearranges with neighbors for "escape" shelters from rain — such as patios with umbrellas, porches and garages. Susan Via, executive committee secretary and picnic chairman for a neighborhood association in Dallas, includes a rain date on the "save the date" postcard to 950 households.

Food and beverages: In organizing a potluck, try the alphabet approach, suggested Allen. For example, attendees whose last name starts with A through J bring appetizers; K through R, salads or sandwiches; S to Z, desserts.

Trash talk: Designating a cleanup committee to oversee trash collection and pickup is necessary for large events. Distribute trash and recycling bins around the party site, and be generous in handing out garbage bags. It gets guests involved and facilitates the chore.

Safety strategy: Anticipate needs, supplies and supervision for first aid attention. Establish a strategy and route for police, fire and emergency medical help, and identify the closest hospital and/or clinic.

Thanks are in order: Acknowledge individuals and groups who donated time, goods and expertise.