One of the oldest models that is still surviving in communication industry and MBA classes is termed AIDA model. AIDA in its expanded form stands for attention, interest, desire and action.
Mostly advertising and sales people use AIDA model. The model is easy to understand and equally easy to implement. According to this model, the firm or the person tries to catch attention of the target audience. For example, a punch line or head line in the advertisement tries to catch attention of the audience. A sales person tries to catch attention by his greeting or professional dressing.
Once the attention is ensured, the time is to move on for creating interest. This is the step in the process that tries to have the target get involved in the sales or communication process. Typically product description or company image take the front seat in an advertisement after the head line. This is to create interest in the target audience mindsets. A sales person tries to evince interest by virtue of talking about the benefits or features of the products as deemed useful by the audience.