Most modern theories of consciousness agree on a definition of "awareness," describing anything that is directly experienced by the waking mind, and perceptible by the "self." Because there are many subjective definitions and experiences, theories focus on conscious perception vs. unconscious instinct.
There are many modern theories of consciousness, and they are loosely divided into philosophical (psychological) and scientific theories.
Philosophical theories of consciousness focus on the subjective feelings and experiences of the individual, trying to codify personal experience with relative experience. These theories are themselves subjective as every individual is different, and are based in instinct-theory and various modes of psychological studies; the goal is to allow the individual a mode of understanding personal behavior through personal experience. Examples of philosophical theories are behaviorism, functionalism, and personal identity.
Scientific theories of consciousness focus on the relationship between the physical nature of the brain (where consciousness "resides") and the sensory input of the body, which is the vessel of experience. These theories are intended to provide a base level of understanding to the function of the biological brain, avoiding the subjective experiences of individuals in favor of a unified scientific theory that explains or justifies most "aware" behavior and thought. Examples of scientific theories are evolutionary (adaptation), consciousness as memory, and higher-order theory.