Social psychologists have determined a few factors that increase the correlation between a person's attitude and actual behavior. First of all, the attitude should be highly specific. Assuming it is specific, then the accessibility of the attitude is an important factor. Accessibility refers to the strength of an attitude, or how quickly that attitude comes to mind in response to the attitude object. Let's use the attitude of hypothetical person Bob towards lawyers in predicting his willingness to intern with a lawyer over the summer.
Accessibility depends on direct experience and rehearsal.
If Bob has had a direct experience with lawyers, his attitude will be more accessible, than if it is only based on opinions he has heard from others.