When approached properly winning planning permission for property development sites is an art as much as a science - although there is certainly a science to it also. When treated just as a science, a numbers game or tick-box exercise alone, then it's highly likely that you will get into trouble. A good architect should deal with the 'art', a good planning consultant deals with the science and the policy and it's the developer's job to understand how everything best fits together; the numbers, seeing the bigger picture, research, coordinating and instructing the professional team.
I mention above negotiate 'where possible', as unfortunately, it is not always possible for a planning permission to be negotiated at local level and sometimes planning decisions will have to be decided by appeal. In an ideal world we would be able to quickly achieve planning permissions (thereby enabling us to quickly supply more much-needed housing) that give the land owner, developer and local community everything they wanted, but alas what we all want is often at different ends of the scale.
Even when developers research and submit planning applications properly, often contractual or other timescales, local politics or difficult planning authorities will mean that dealing with things via the appeal process is the only sensible option.
The application & decision-making process
Before I explain how to decide upon the best strategy for winning planning permission it's important that you understand exactly how the application & decision-making process works.
Firstly, it's useful to know that planning applications are usually categorised as being either 'major' or 'minor'. For dwellings, a major development is one where the number of residential units to be constructed is 10 or above. Less than 10 dwellings is considered a minor application. Central government has set 'targets' specifying that minor applications should be dealt with within 8 weeks and major applications should be dealt with within 13 weeks. In reality, these targets are rarely met and planning applications usually take much longer.