Going through the structure of the paragraph
There is no one answer or solution, this is just one opinion of how the paragraph can be improved. Comments on some of the problems with the paragraph are in bold.
It was the invention of several practical items which enabled the formation of the new teenage subculture. This is not a good topic sentence. This does not reflect what the whole paragraph is about. Advances in the petrochemical industry allowed the production of nylon and polyester. Stretchy clothes with colourful prints could be made for the first time. Young people stepped away from previous limitations. Prior to the 1950s, ‘teenagers’ did not exist. Young people were referred to as either children or adults. Children listened to their parent’s music and dressed in similar clothes. Teenagers are often viewed as a segregated section of society. It is a stage of life which is taken for granted. The term ‘teenager’ is actually a fairly modern invention. These sentences are all very short. They read like a list and do not follow a logical train of thought. During the 1950s, family life in Britain was revolutionised, resulting in the ‘birth of the teenager’. Rock and roll exploded onto the scene and gave young people music they felt passionate about. Rock and roll only occurred following the invention of the first mass produced, solid body electric guitar. The development of the transistor meant cheaper, portable record players replaced heavy gramophone players. These sentences are linked in terms of their subject but they need connectives to show links between the ideas and a flow of thought. Teenagers could play music in their bedrooms for the first time. We often associate teenagers with a pursuit for individual identity. This sentence does not round off the ideas in the paragraph – it may be acting as a link into a subsequent paragraph, but it does not flow from the preceding sentence.