-It's no longer a matter for discussion. When it comes to skirt and pant lengths, anything goes. The knees and ankles show or don't show according to personal preference. Designers Bill Blass, Oscar de la Renta, Carolyne Roehm and Carolina Herrera are showing short, as high as mid-thigh. Donna Karan, Louis dell'Olio for Anne Klein, and Patricia Pastor of Perry Ellis will show a combination of long and short. Ralph Lauren prefers long to just below the calf, and Calvin Klein's lengths will cover the knee. The only guidelines now are related to proportion, ease of movement, good fit and personal style.

-The biggest trend in fabrics is toward sheers. There are soft sheers and crisp sheers; sheers in plain and print fabrics, layers of chiffon, organdy, georgette, voile, organza, mousseline, lawn and lace. Sheer blouses and dresses are shown worn over camisoles in a coordinating color. As an update item, a chiffon scarf is an obvious option.-Designers are adding more subtle shine to clothes and accessories - a soft, metallic shimmer that looks best when made up in fluid fabrics like silk lame. Fashion's sheen comes packaged as solid silver, sparks of gold and the metal-like shine of satin and sequins. The new metallics mix well with black and white. They clash with brights and blind the eye if paired with even more shine.

-Navy blue shows up as a key color for spring. Navy is so pervasive that it literally becomes the uniform color for day and evening. Designers are choosing navy over black, brightened against white accents, embellished with gold buttons or on its own without any decoration at all. Navy implies the strictness, the neatness and the discipline of a military uniform, making it ideal for tailored business dress.

-If you value physical comfort and fewer decisions, you'll love to slip on a jumpsuit. Stores are full of them this spring. Before you buy, try it on, bend over, sit down, move around, make sure it fits. Check for enough width across the shoulders. Double-check length in the midriff, making sure the waist aligns with yours. Comfort is quickly gone if the crotch fits tight.

-The vest - the stuffy, least-worn member of a man's three-piece suit, borrowed by women in the '70s but out in the '80s - has reappeared as a woman's fashion item for spring '89. Attention is centered on shaping and ornamentation.

The new vests range from sporty, tailored styles and folkloric boleros to Chanel-inspired versions, complete with gold buttons and contrasting trim for day, and from crocheted lace to gold lame or hammered satin for evening. Ornamentation is seen in the way of beading, applique, braid and embroidery.

Sew a vest for yourself with Vogue Pattern No. 7335. Worn under a jacket, it looks right for the office. Layered over a notch-collar shirt, a vest is the perfect alternative to a sweater, but often it's worn over a cotton T-shirt instead. A vest goes solo with the younger set, slipped on over skin for warm days or evening. Buttoned high, vests make the newly fashionable sheers really wearable. Worn open, they give full view to the ruffled shirts with lacy collars and full sleeves so popular this spring. The look is paired with flared bell-bottom pants.

-A scarf is no longer an accessory only. Designers are focusing attention on the upper body, using scarves to soften and romanticize necklines, wrap torsos and frame the shoulders. Giant-sized, a vest can be knotted and draped like a toga or wrapped and tied around the body like a sarong, worn under a tailored jacket. A versatile item, scarves show up as a blouse, a halter top or a dress - an essential piece of clothing.

-Today's trend in eye makeup is toward multipurpose products, whether it's eyeliner pencil that doubles as a shadow or mascara that works for brows as well as lashes. Mascaras now come colorless. They look and work much like the gel for your hair. The objective is to define by adding texture and gloss, thickening lashes. What's more, they're perfect for shaping and holding brows in place. On lashes or brows, colorless mascara is great for young teens just beginning to experiment with makeup.

-"The flip is back," quipped America's second lady, Marilyn Quayle. While she referred to her wit, her flip hairstyle is finding its way back into fashion.

Quick and easy, today's flip is not dependent on rollers and hairspray. Improved haircutting, curling irons and hot brushes make flipping easier to maintain.

The return of the flip is only part of fashion's return to the A-line shape, echoed by the return of the trapeze dress - newly called the swing or pyramid, with a small bodice and sweeping skirt.

If the flip, the trapeze and bell-bottoms are back, can the beehive be far behind?