In a quiet park a short walk from the noise and bustle of the Occupy Wall Street protest in lower Manhattan, a handful of activists sit on the ground and talk tactics. They are members of the direct action committee, one of several "horizontal" working groups that have sprung up to ensure the protest is kept in the public eye.

Occupy Wall Street member Ray Mia: 'We have to make things a little sexy and badass.' (Photograph: Karen McVeigh for the Guardian) With no leaders, no list of demands and a focus on a democratic, decentralised system of general assembly borrowed from protests in Spain, Greece and Tunisia, it is a major challenge to retain momentum and make decisions that speak for everyone among the few hundred students, campaigners and others camped out at Zuccotti Park and their wider network of supporters. Discussing tactics in the open, where anyone – committee members included – could be an undercover police officer, presents another.

Yet over the last three weeks, the protesters have organised peaceful marches, forced a reluctant US media to take notice, run PR rings around the New York police department and watched the action spread to other cities across the US. Even events that have turned nasty, such as the pepper-spraying of female demonstrators by a police officer and the arrests of 700 activists on Brooklyn bridge, have been turned to Occupy Wall Street's advantage.

The direct action committee lies at the heart of this success. Numbering anywhere between 35 and 50 activists, the committee is "empowered by the general assembly" to plan action. The committee includes campaigners, community activists and those with relevant organisational skills, some of whom live in collectives and already base their lives around a communal system.

At the meeting in the park earlier this week, there were 12 of them, one sprawled on his front, taking minutes to feed back to the general assembly, others still wearing zombie make-up from a stunt earlier in the day. The subjects under discussion included security, march procedure, how to deal with "autonomous" actions and how to avoid conflict with police. Members stress they plan only legal actions, but would not act against unlawful protest by individuals.

One of the ideas under discussion this week, for example, was a peaceful action to disrupt banks, though no final decision was made.

"Part of direct action and civil disobedience is we have to make things a little sexy and badass to get people's attention" said committee member Ray Mia, 25, from New Jersey. "We are hoping to move forward and to do new stuff, to be more creative."

The committee also discussed the events of Saturday, in which, they say, provocateurs urged protesters away from the planned march on the pedestrian area onto the Brooklyn bridge roadway, leading the police to move in.

Although each course of action is taken semi-collectively, there are key things that only a handful of people know, or are supposed to know, said Mia. She said the decision to march on the bridge had been taken a week before the event, but in the end, it became an open secret. "We wanted to keep the location under wraps," she said. "We failed at Brooklyn bridge, but we had a contingency plan, which only six of us knew about."

The committee appoints several "pacekeepers" for every march, who make sure it doesn't go too fast or too slow, and it is they who decide on the direction. There are also informal "scouts", who keep an eye on progress, and "runners" who run back and forth between the various organizers telling them of any problems arising.

One of the problems of the Brooklyn bridge march, they decided, was that warnings from pace-makers at the front about the threat of arrest if protesters moved onto roadway were not communicated to those further back. So the committee agreed to put in place a more formal system of scouts, runners and pace-keepers for the next march.

Mia talked about the difficulty of planning direct action with relative strangers. "Direct action is often done by affinity groups, people who know each other well. We're in a position where we have only known each other two weeks and we are doing it in public, surrounded by police. Even having my cell phone off with batteries in, they can listen in to what I'm saying."

Ari Cowan, Occupy Wall Street One of her fellow committee members said that police officers previously seen arresting protesters had been spotted undercover at the camp. Ari Cowan, 21, a community organizer from San Francisco, who has worked with Migrant Justice, agreed: "We're all learning together. The process informs us and allows us to learn from each other. We continue to refine how we plan marches and other protests."

Cowan said that, in order to allow a diversity of tactics - where for instance, the majority of people want to protest legally and peacefully, but others are happy to commit acts of civil disobedience to get themselves arrested - they have to plan carefully. "It's a continuing evolution about how to keep people safe and allow diversity of tactics. It's about creating an institutional memory."

Even those within the group say that Occupy Wall Street is a unique protest.

Occupy Wall Street activist Anthony Yenafuck

Anthony Yenafuck, 28, a freelance graphic designer, from Idaho, said: "This movement doesn't look like anything I've ever seen. Most demos or actions are like: 'We're going to show up at this march, put out a press release', and then that's it."

One of the most frequent questions asked of the protesters is about their demands, about what they want. However, what unites them is more often what they don't want: their rejection of what they say is a corrupt political and financial system which rewards the rich and neglects the needy.

One of the key goals, the protesters say, is building a new system. "People ask about our demands, but we are not saying: 'We're powerless, we want to ask'. If anything, we are going to list our goals as we are building them," said Cowan.

"It is about the world we want to see, a world we are happy to live in where we feel respected and our voices are heard and respected. It allows for continual evolution. We are building the community we want to live in and we're doing it in public."