Great job with such a convincing essay!  Be careful when you write long sentences, and make sure that you don't accidently create a run-on sentence.  I am on the side of a fashion victim.  I think fashion trends and the need to stay up-to-date can create too much competition.

Fashion trends have been an important matter within our society. Its importance is growing each day, and now we can observe how a person could be defined by his or her its way of dressing.

It is known that a largewide part of the population always has have always in mind the need to wear necessity of wearing the latest fashion product(s), in order to feel up-to-date attached to the latest style, even if they have to spend a lot of money on it. On the one hand, this could lead to a lack of personality due to the need to have of having the best product available onin the market, just to show that you are better than other people the others ("the others" sounds a little out of place to me in this example). On the other hand, a person could stillhave/maintain(I think
"maintain" is more descriptive better)his or her its own style as, and this could be reflected by the acquisition of the clothes that each person loves. In addition, Many a lot of ("a lot" is a bit to informal for an essay)reasons could be arguedsummarized, either from the point of view of a fashion victim or from the perspective thought of a person who just want to follow a specific style.

The importance of being consistent infollowing one style or another should be decided by each person individually. However, the advertisements that the big companies are always displaying throughout the year, makes it difficult to keep up follow, due to the weak minds that mostly teenagers have while watching the new commercial of/with their favourite singer.

In my humble opinion, even if the companies/businesses firms want us to wear or to buy the products they create, we should be cautious/skeptical stronger than that so that we could follow our own judgement while/when buying something. Therefore, our own style regarding fashion should be selected by our own likes, avoiding the rules of the most powerful companies.

Our appearance; the way we dress, etc., reflects who we are. It is important to be consistent in the styles of dress we adopt throughout our lives. 

Fashion trends have been an important matter within our society. Their importance is growing each day, and now we can observe how a person may be defined by their way of dressing [style of dress].

We know that much of the population believes that it is important to wear the latest fashions in order to keep up with the latest trends, even if they have to spend a lot of money. On the one hand, this could indicate a personality flaw because of their need to own the best products available on the market in order to show that they are "better" than others. On the other hand, one may create their own style, and this may be reflected by the acquisition of the clothing that they love. In addition, many reasons can be summarized, either from the point of view of a "fashion victim," or from the mindset of a person who just wants to follow a specific style.

The importance of consistantly following one style or another should be decided by individual, yet the advertisements that big companies promote throughout the year make styles difficult to follow. This is because most teenagers are easily impressed by their favorite singers appearing in new commercials. 

In my humble opinion, we should follow our own judgement when we consider what to purchase.  Our individual fashion sense should reflect our likes and dislikes, not the rules of the most powerful. 

Essay. Practice for the CAE exam :)

Essay: Our appearance, the way we dress, etc., reflects who we are. It is therefore important to be consistent in the style we adopt throughout our lives.

Fashion trends have always been an important matter within our society. Its importance is growing each day and now we can observe how a person could be defined by its their way of dressing.

It is well known that a wide large (better word for this sentence) part of the population have always in mind the necessity of wearing always find it neccesary to wear the latest fashion product, in order to feel attached to the latest style, even if they have to spend a lot of money on it. On the one hand, this could lead to a lack of personality. This is due to the need for having the best product available in the market just to show that you are better than the others. On the other hand, a person could have their own style and this could be reflected by the acquisition of the clothes that each person they love. In addition, a lot of reasons could be summarized, either from the point of view of a fashion victim or from the thought of a person who just wants to follow a specific style. 

The importance of being consistent following one style or another should be decided by each person individually. However, the advertisements that the big companies are always displaying throughout the year, makes it difficult to follow do, due to the weak minds that mostly teenagers have while watching the new commercial of their favourite singer.

In my humble opinion, even if the firms companies want us to wear or to buy the products they create, we should be stronger than that, so that we could follow our own judgement while buying something. Therefore, our own style regarding fashion should be selected by our own likes, avoiding the rules of the most powerful.

An excellent argument, I really enjoyed reading this piece! :)

Remember in English writing: 

- when using a comma ',' you only have to put a space after the comma, not before it

- when using 'and' you do not use a comma, as 'and' joins 2 ideas in a sentence