Psychologist Abraham Maslow came up with a theory which described the hierarchy of human needs. Whether or not your product is essential to human survival, it will fall into one of the categories in Maslow's hierarchy of needs. If you know which of these needs you should market to, it will be that much easier.
The first tier of Maslow's hierarchy is that of physical needs. Without these, humans could not survive. These are things like oxygen, water, food, and shelter, and also homeostasis regulating activities like sleep.
The hard part about selling a basic product or service that everyone needs is the immense competition from commoditization. For example, everyone needs to eat. However, what are you going to do to make your food appeal to more people than the burger joint across the street? Some of the solutions to this dilemma might be offering lower prices, tastier food, pleasant service, or a more hospitable eating area than the competition. Of course, the food you are offering should be such that it automatically becomes high on a customer's list of choices.
After that, the next stage of Maslow's hierarchy has to do with safety and security. Watch a few minutes of television and you will be inundated with advertisements for security companies, life insurance, and all manner of "safety nets." How would your product make your customers feel safer and more secure? Letting them know how your product can make them and their family safer gets to their root emotions and can be a main selling point.
Maslow's pyramid maintains that love and belonging is the third basic human need. Everyone can relate to the longing for intimacy, whether among friends, family members, or a significant other. If you own a personals web page or singles club, use this knowledge to your advantage. Make sure to play up the social benefits and increased levels of friendship they will gain by using your service, and cite user testimonials. Reading real peoples' positive feedback is a decision-maker for most potential customers.
Maslow also makes note in his hierarchy that esteem is another driving human need. Esteem really has two areas. One area is satisfied by receiving recognition, appreciation, rewards, or respect; the other area is self-esteem, which really requires a person to feel good about himself, be independent, and have a healthy sense of self-respect and self-confidence.
I am reminded of a shampoo commercial in which the lead actress walks through an office building with the admiring eyes of many workers following her around. At the end, she walks into a board meeting and states that she doesn't even work for the company, and all the attention must be the result of her shampoo.
The ultimate level of the Maslow Hierarchy is that of self-actualization. This is the "be all that you can be" attitude that encourages individuals to strive and make an effort to be responsible and participatory citizens in the world today.
So long as you don't go too far, you can get your customers to notice you by making it clear how you can satisfy their needs. It will be helpful if you know what means of psychological motivation are effective on you and on your target audience.