Accessories. They're the difference between being well-dressed and just plain dressed. This was a major story emerging from the Men's Fashion Association spring and summer press preview recently held in Los Angeles.

As fashion editors from across the country watched good-looking clothes for warm weather parade down the runway, it became increasingly clear: little things mean a lot in the world of male apparel. You can go out and buy an expensive designer suit. You can find the most perfect sport jacket in the world. But if you don't add the right finishing touches - well, the outfit's going to end up looking - perish the thought - ordinary.We're happy to say there's no need for such a disaster these days. Some of the handsomest finishing touches you can imagine are being turned out by the menswear industry and soon will be arriving in the stores. They run the gamut from ties to shoes. And these are the stylish trends to watch for. . . .

TIES: Art deco prints are coming on strong for spring, according to the MFA. The tiny stripe, the small and unassuming pattern, belong at the back of the closet for a while. Opt instead for something bolder - very bold, if you dare. That's the hot news at the moment.

As for dimensions, ties are much wider and have smaller bottlenecks, reflecting the influence of the '40s. Important new designer names in cravats are Format and Modules.

BELTS: Those old standbys, plain leather belts, look very old-fashioned all of a sudden. For spring, accessories designers are touting belts that are enhanced with perforations, webbing, kilties and hardware. The same belts now work for leisure and business dressing.

SUSPENDERS: The hit of last season is continuing on - stronger than ever. Especially popular for warm weather will be suspenders in silk and cotton. Interesting prints are being shown; often, whimsical prints. The color purple, which is making such an important fashion statement at the moment, will frequently be seen, and it will add just the right fashion-forward note to many outfits for business and sport.

SUNGLASSES: Frames that hark back to the '30s, '40s and '60s will be in the spotlight for spring and summer. Watch for little round glasses, similar to those once worn by famous Beatle John Lennon. Watch for the aviator style.

Just about anything that's retro will look right up to the minute, according to the MFA.

HOSIERY: Patterns are where it's at. Even for the most conservative business occasions, stylish execs are opting to wear socks that feature discreet patterns.

When it comes to hosiery for sport - well, pull out all the stops! There never has been such a wide selection of inventive, colorful and clever hosiery in the history of menswear.

Clever socks for leisure will make you look stylish and cheer you up at the same time. Sunny colors abound. And, oh, how witty some prints are! E.G. Smith, that fellow who revolutionized the hosiery market with the slouch sock, has created a smiley-face motif. There are tie-dye socks. There are wildly striped socks. There are socks featuring bold argyles and polka dots. Fun stuff is everywhere in the market! And why not? For far too long, men languished with navy and black and basic brown. It's high time some creativity entered the field.

SHOES: To go with the new bold and creative hosiery, footwear designers are showing all kinds of fun footwear. The ever-popular sneaker is in the spotlight for leisure. (At MFA, Keds were shown with socks and without. Both looks, said Chip Tolbert, the organization's fashion director, are perfectly acceptable for spring and summer.)

Loafers also are being promoted by leading fashion authorities. And, they note, there's no reason why this style can't be worn for leisure and to the office as well. Indeed, if you haven't a great deal of money to spend on warm weather attire, choosing a loafer would be a smart way to go. The style can do double-duty in your accessories wardrobe.

Your accessories wardrobe. It pays to continually work at building one, according to the MFA, because accessories can vastly increase the possibilities of the clothing you own.

Few can afford huge closets full of clothes these days, says Tolbert. The cost of living's just too high. The only way to be well-dressed on a budget is to choose accessories wisely and use them to give a few outfits a variety of looks.