Take a look around-you will be amazed what you can learn about trends. The barometers are many-hipsters and soccer moms are re-writing fashion history. Gone are the days of style moguls dictating the look, now the style moguls are sending their minions out to check out the street. Style is being re-invented and custom tailored for a thousand "niche" markets.
The beginnings of dressing as self expression go back to the sixties and still deeper to the 19th century fascination with exoticism-Isadora Duncan and Mata Hare are early explorers of Fashion as self expression. Coco Channel turned the western idea of fashion on its head, women no longer had to be bound in layers of boning and fabric, she perhaps more than anyone was a "Columbus" heralding a new age of thinking abut fashion. When young people rejected their parents attitude about dressing in the sixties they owed more to then established fashion icon Channel then they could ever realize at the time. No longer bound by norms people turned to other cultures, explored the roots of their own culture or created fusion styles never dreamed of.
Dressing has always been used as a form of expression but generally it was for ideas mutually held by whole cultures. Gypsies wore gypsy skirts peasants wore peasant skirts heiresses wore grand dresses. Now an heiress is more likely to wear a peasant skirt than a peasant. We now accept fashion as "expression" formally it was to denote social standing or for functional reasons. Ever the realm of functional clothing has been explored by adventurous fashionistas dawning workmen’s coveralls or cowboy dress as pure fashion. Jeans are the most famous example of functional clothing rising from its humble workmen’s past to fashion super star status.
Today the rules that were broken are long forgotten, style is global and local, rules no longer apply. If you are out trying to figure out what to design next or how to create "looks" for your customer-well turn to the source. I think people sometimes over complicate trend reArray, looking at your customers or would be customers is a good place to start. There is no use making something that does not fit their lives-well at least if you are trying to sell to them. Getting the right pulse is observation, inspiration and a lot of leg work.
There are those who thrive on just doing what they love and building a market around it-a lot of smaller fashion labels start this way-remember Channel was once a small renegade label, hard to believe. Popular stars now have a tsunami like effect on what people want to wear-a movie can suddenly have people running to find Japanese inspired skirts or middle earth jewellery. Look out for the wave if you are trying to figure out trend, or create your own trend if you want to be the next fashion revolutionary.