Retailers adjust marketing techniques and salesmanship to fit the product

''We like the home furnishing supermarket idea for our carry-out-and-assemble-yourself stores,'' says Richard Butler, who with partner Ron Barnum owns The House Store in Chicago and a new branch in Downer's Grove, Ill.

''We try to show as many good ideas as possible through the examples and settings on the floor. Then we make it easy for people to identify and fetch the packaged goods out of bins and get it to the checkout counter. We see that all instructions are simple and explicit,'' Mr. Butler explained as we explored all the nooks and crannies of the Chicago store.

This type of store, he says, is made to order for those who want ''instant gratification.'' Customers can look, buy, take home, assemble, and use all in the same day. No waiting for delivery or anything else.

''Things have changed a lot since we opened in 1980,'' commented partner Ron Barnum. ''Quality has improved. The amount and variety of merchandise available has expanded greatly. And a new formalism has joined the casual look. We go to the Scandinavian Furniture Fair in Copenhagen every May to find many of our best lines.''

As to color, black sells as fast as white at The House Stores, and red has become a key color.

What sells best? ''Anything that organizes people and possessions. With space at a premium, customers are looking for pieces that will bring more order into their lives.''

''Our aim,'' says Mr. Butler, ''is to offer good contemporary design at a moderate price. We don't call ourselves a life-style store. We think of ourselves as a design store. We offer lots of choices and options, and we find that people are pretty savvy these days about putting things together.

''This kind of furniture is becoming more of a mainstream thing,'' Mr. Butler continues. ''We feel it is important not only to have tried-and-true staples, but to keep finding innovative new products that can offer new looks and new solutions to old furnishing problems. We keep listening to what customers want and need. If we don't find it on the market, we design it and find a company that will make it for us.''

Steven Woodward of Dallas owns three ''Bright Ideas'' furnishings stores there that specialize in ready-to-assemble furnishings. ''This is an unusual kind of business that requires a special kind of salesmanship,'' says Mr. Woodward. ''You have to love to help people figure out what they need, what will fit, and how they can best combine the various components you are offering them.

''We give people the best price we can,'' he says, ''then help them load the cartons into their cars, and then take a personal interest in seeing that they get the pieces together properly.

''Because we cater to people whose budget is important to them, we offer one-year financing and let them pay it out by the month. If someone is all thumbs when it comes to assembly, we go out to their home and put pieces together, for an additional 10 percent of the purchase price.

''We tell every customer to call us if they strike a snag when they are assembling pieces themselves and usually we can help them over the hump right on the telephone. We find that if we can help people to complete the assembly themselves, and enjoy that satisfaction, they become better customers.''

Mr. Woodward says many of his customers, after examining all the options and figuring out an overall plan, buy a few basic pieces but then keep adding a piece or two at a time.