NLP consists of a number of models or ideas, and then tools and techniques based on those models. The major models usually associated with NLP are:

1. Sensory acuity and physiology
Thinking is linked closely to physiology (mind and body are the same system). So people's thought processes can change their physiological state. Sufficiently sensitive sensory acuity will help a conversationalist fine-tune their communication to a person in ways over and above simple, basic linguistics.

2. The "Meta-Model™"
A set of linguistic challenges for uncovering the "deep structure" underneath someone's "surface structure" sentences.

3. Representational Systems
These actually appeared in Erickson's work and the work of others, though Bandler and Grinder took them much further. Different people seem to represent knowledge in different sensory modalities. Their representation is revealed visibly in their language. Often, communication difficulties are little more than two people speaking in incompatible representational systems.
For example, different people express themselves in different forms. Even the same experience could be described differently, depending on the speaker's representational system:
Auditory: "I really hear what you're saying."
Visual: "I see what you mean."
Kinesthetic: "I've got a handle on that."
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4. The "Milton-Model"
This is a set of linguistic patterns Milton Erickson used to induce trance and other states in people. It is the inverse of the meta-model; it teaches you how to be artfully vague, which is what you use to do therapeutic hypnosis with someone.

5. Eye Accessing Cues
When people access different representational systems, their eyes move in certain ways. Lots of research has been done on accessing cues, because it seems easy to test. In some people eye accessing cues are easy to spot, in others they are difficult or even impossible without training and experience. But why not try it for yourself. Click here for a picture that shows where people look.

6. Submodalities
The structure of internal representations determines your response.
For example, picture a landscape you really like. Make the colors more intense. Now turn the color down, until it's black and white. For most people, high color intensifies the feeling, and b&w neutralizes it. The degree of color, part of the structure of the representation, affects the intensity of your feelings about the content. This example is in the "visual realm". There are submodalities for each representational system: visual, auditory and kinesthetic.

7. Metaprograms
These are aspects about how people process information and make decisions.
For example, some people are motivated TOWARDS GOALS, while others are motivated AWAY FROM non-goals. TOWARDS or AWAY-FROM tells how they respond to their world. NLP has several techniques for diagnosing and intervening in certain situations. They have a phobia cure, a way to de-traumatize past traumas, ways to identify and integrate conflicting belief systems that keep you from doing things you want, etc.