What do you mean specifically? There are at least three main approaches, all of which mean that you will be developing your model of cognition from very different perspectives and using different research methods; there's the symbolic approach, the connectionist approach (also known as neural network theory), and then there's dynamical systems theory, and probably many more as we keep developing new theories and solutions to adaptive problems!
Let me briefly outline an avenue I have followed to try out the development of a generalized model of cognition, though not that generalized because my aim was to deal with social cognition. However, the scope of the model in question may reach beyond social cognition and may be a case in point of Meadhbh's symbolic approach.
My starting point was the idea that cognition may be conceived of as a representational system serving to model representations of what we may call "the world." The next idea was that also language is a representational system serving to represent the same world. Hence general design features of cognition may be derived from linguistic universals (or quasi universals) may. In this way, Noam Chomsky has suggested that the quasi universal noun-verb distinction may reflect a cognitive universal implying that the cognitive field is organized as a network of relations between entities. Hence a general model of cognition may proceed from entities and relations between the entities. another relevant linguistic (quasi) universal was found in pronominal categories that enabled to conceive of the entities in two ways. On the basis of those elements a model was constructed and during more than 30 years one of my academic hobbies was to have the model confronted with empirical data. One main outcome was that people seem to handle two alternative programs to process the same input. One program leads towards what may be called a personalized view, the other to a depersonalized one as in natural sciences. Most of the research on the model has been published in journal articles and book chapters spread over 30 years. However, a concise overview can be found in the theoretical sections of two attached articles I published before my retirement.
It may be worth mentioning that some of the outputs of the research based on the model made their way in the community of researchers on social cognition (e.g.: the concepts of self- and other-profitability / self- and other-favouring), but the the model from which those outputs were generated is neglected. Nevertheless, taking the model into account it would be possible to demonstrate a common basis of concepts that belong to apparently unrelated fields.
Peeters, G. (2004). Thinking in the third person: A mark of expertness. Psychologica Belgica, 44, 249-267.
Peeters, G. & Hendrickx, A. (2007). The dual self: First and third person categorizations of the self and the role of objective self-awareness . Psychologica Belgica,47,145-171.