Within the public realm, urban design guidelines are one set of a range of instruments used to control or influence public and private works so as to optimise the production of reliably 'good' built environments. They address the public domain of our cities as well as private domain impacts on the public domain. Guidelines are public documents, which to be successful their basis must be accessible for critical review. This is necessary so that guidelines can reflect shared community values and be accountable. The model in this paper describes 'good practice' procedures for the preparation of guidelines that are based in theory and practice. It includes discussion on substantive matters that are relevant to built environments. It seeks to establish high quality decisions as well as high quality information upon which decisions are made. Both the information and decisions are intended to be transparent and thereby accountable. The model is grounded in critical study of existing urban design guidelines in Australia and overseas as well as in theories and methods derived from the literature. It is structured to reflect a managed problem-solving approach under the headings of: intentions; preparation; implementation; performance. A further heading, 'substantive content' parallels the other headings and addresses the subject matter of guidelines with cross reference to underpinning theory texts and to analysis techniques. The model is not a sequential action checklist, but rather is a heuristic one wherein each step may inform previous steps and thereby potentially modify the conclusions of that step, and in turn the outcome, which may be tested. However such 'reflection-test' processes cannot proceed indefinitely and informed decisions are expected to be made within time and budget constraints. It brings theoretical and practice knowledge together to help produce better functioning built environments within which aesthetics and symbolism are considered as functions, in the Lang sense (1994) of human concerns being a function, together with physical, ecological and economic aspects.