Your first and most obvious requirement is a group of residents who are prepared to take an active part, never easy when everybody's busy, or, as with many London blocks, large numbers of flats are sublet. But the more tenants you get involved right from the start, the less likely it will be that one person ends up with all the work. Then it's important to sound out the views of all the leaseholders, including absentees. To be effective, your association needs to represent the whole block, not a small clique. If there's a consensus that an association is a good thing, it's time to elect acting officers, who will draw up a constitution to put to the other residents at an inaugural meeting. Here some help is essential.