Separates: performance with pizazz

For the majority of women these days, dressing comes down to a matter of arranging and rearranging a wardrobe of separate sportswear pieces. As Paris designer Angelo Tarlazzi said recently: "You take the same elements and put them together in different ways. That's fashion today."

The separates update has become a seasonal activity. Since women spend good money on their basic jackets, skirts, pants, blouses, and shirts, they expect lasting performance in return. But after being the daily style fare for a while , even the most handsome piece grows stale. When that happens, fresh changes in the fashion menu are indicated.

Most movable sportswear parts are standardized staples. Lengths, proportions , and details may change, but a blazer remains a blazer; a skirt, a skirt. Outside these restrictions are the free areas of color, pattern, and texture -- three elements with which one can play around ad infinitum.

This year, designers suggest a more adventurous approach to giving one's sold duds of yesteryear a new twist. They lead the way by showing velvet, a fabric that has of late been generally associated with dressy occasions, for all times of day. A dark velvet skirt with a jacket of tweed or flannel in a contrasting color was one of the big messages in advance fall showings.

Things that traditionally have not "gone together" are now expected to be put together in uninhabited ways: stripes, plaids, checks, and foulards in the same outfit, for example; velvet with shetland; lace with cashmere and paisley.

Women who wouldn't hesitate to mix patters in decorating their bedrooms and living rooms will catch on to these new free-wheeling ways of assembling their turnouts without any trouble. The trick is to stick to two or three basic colors and let the patters and textures of separates (and the addenda worn with them) fall where they may.

In assembling an outfit, it is wise to strive for a particular effect. The leading "looks" -- Victorian, Scotish, flockloric (particularly Peruvian), and Hapsburg -- will influence choices. A lace collar, a jabot, or a lace-trimmed blouse will Victorianize tailored pieces. A tartan shirt or a tam plus muffler draped Highlander-style across the shoulder will add the Scots note. With a scarf tied under a felt fedora plus a sweater in a folkloric design, the Peruvian idea takes over. A Tyrolean hat and loden cape with velvet collar puts an outfit in the Austro-Hungarian mood.

The boiled wool jacket traditionally worn in the Austrian Alps has risen in chic this season -- and in price too. Skiers who remember buying the silver-buttoned jacket in Kitzbuhel for the schilling equivalent of $16 in the 1960s will be astonished to find the import selling in America at around $260 in 1980.

In other respects, the separates picture is only somewhat changed this season. There is a wealth of choices, as racks and racks of clothes in the sportswear departments attest. Plaids and tartans of all sorts are particularly plentiful, with the Scottish kilt holding a strong position. Madras-type plaids a tweed jackets are a new note.

Bordeaux, forest and bottle greens, purples, and cinnamons as well as strong pastels have been added to navy, black, brown, and red -- the classic colors for the so-called "preppie" fashions that all America wears. Assortments in this look from one manufacturer alone -- J. G. Hook -- seem to answer every want, from the gray fannel pleated skirt to the muted check blazer. The expectation seems to be that many women will be adding to the sums of their separate parts this year.