Clovin Ruffin, who has designed very successful collections of simple dresses selling for about $50, says his customer is growing up and is ready to spend $75 to $150 of one dress rather than the same amount for two. He's done a collection with the same kind of nice, simple bodies, though a bit looser, still body-revealing. The difference this time is the far better fabric. Sketched above is a group of his designs in (from left) rayon lace, Qiana and wool. (His dresses are available at Woodies.)

If the label and the talent's familiar, but not the face, you'll have a chance to remedy that with a lot of designers this fall. Starting late in August, the parade of designers passing through Washington will include Adolfo, Joan Sibley, Don Sayres, Oscar de la Renta, Bill Kaiserman, Bill Blass, Mary McFadden, the Missonis, Albert Nipon, Valentino, Don Robbie. And all that (and probably more) before Sept. 24, as part of a few Washington stores' efforts to distinguish themselves from the competition.

It had to happen, though. Scheduled for the same day, two of the most appealing shows. Bill Blass will be there to show his collection for the benefit of the Corcoran Gallery at the renovated Lord & Taylor in Chevy Chase and Tai and Rosita Missoni will have a benefit showing at the Folger Gallery for Bloomingdale's, both on September 8.

If the name Diane Johnson is familiar, but you can't picture the face, check the August issue of Glamour magazine. Johnson, producer and host of Women's World on WOOK-FM was chosen by Glamour as an outstanding college student from 750 candidates. Basis for the selection was campus and community activities, a scholastic achievement and work experience. Johnson graduated from American University and was producer and host of a show D.C. schools when her proposal for an hour-long talk show was accepted. Her show is aired every Sunday.

"Psychologically speaking, a morning shower, or even a bath, is similar to donning off armor before going out to do battle with the challenges of day," reports motivational research expert Dr. Ernest Dirchter in a study conducted on bathing for his client, Dial soap. "A shower prepares you for the day ahead. And at the same time, it helps generate hope that this day will be better than the last."

Dichter assigns moral overtones to bathing as well "Many people today still believe that a 'clean' person is a moral person and that, in turn, moral person lives longer. It even relates to the act of baptism or absolution - a 'cleansing' of the soul."

Women are spending more time in bathrooms which no longer the "forgotten" rooms, but which now get all the attention of a decorator with dyed-to-match towels, tissue paper and even soap.

According to Dichter, some people associate bathing with the process of taking inventory, "It's like checking out your body to make sure all the limbs are still there," says Dichter. "For others, and young people in particular, psychological security is very important. Bathing takes on the form of self-assertion. You're starting out fresh and clean with an overall good feeling about yourself."

Fashion tips from the Men's Fashion Association, There lie flat and don't create a bulge.

Suggestion pour in for keeping cool in the summer. In this week's mail, one good and one bad. First the bad: Sleep on the floor on a dampened sheet. Now for the good: Marilyn Monroe's cool tip from "The Seven-Year Itch" - put your undies in the refrigerator.

Only 199 shopping days till Christmas (19 more if you count Sunday openings), a worthwhile thing to remember when you consider the gift possibilities on the current sale racks in every store in town.

Speaking of bargains, one of the best buys in town is the 10-cents Coke at Up Against the Wall. The store uses a machine that won't let you pay more than a dime. And at E.F. Slys Five and Dime in Landover, MacKeen's girdle-tight jeans are $25; they sell in New York at The French Jean Store for $65. The store's plot is to keep the $25 until their stock of 500 jeans runs out as a way introduce the jeans to Washington.

Now the word is out as to why those clothes in "Annie Hall" are so appealing. Buffy Birrittella, assistant to Ralph Lauren, called to say a credit is due for all the clothes in the Woody Allen clothes, on and off stage as well as the lastest things in Diane Keaton's closet. The Keaton clothes for the flick were a mix of new Lauren designs and Keaton's old favorites from the back of her closet.