Every era has a set of Key Ideas which people who come after them look back and identify.  All the ideas may not apply to all authors or people, but in general they represent the attitude and genre of the period well.  For the 18th Century, these ideas are:

 •Politics  •Wealth and Poverty  •Elegance and Reason  •Technological and Commercial Advance   •Journalism   •The development of the novel

Every era rebels against the one which came before it in some way, fashion, or attitude.  The 18th Century rebels against the "haves and have nots" attitude of the Renaissance.  The focus changes for the 18th Century on the values and life of the middle class rather than solely on the upper class.  The concerns included work, domestic relations, and social respectability.  They urged public manners and morals.  They focused more on reason and logic than emotion and imagination.  They focused more on elegance and social correctness which would help the middle class take more pride in itself as the backbone of the nation.  Social work was a huge focus as people like Dickens and other critics repeatedly pointed out the impoverished condition of children, widows, and other less fortunates on the street. As you can see from the Key Ideas, industry becomes a focal point as well.  More people moved from the country to settle into cities and looked for jobs in the factories and other industries available in larger cities.  With more people moving into the cities, there was a greater focus on individual needs as opposed to society as a whole...more people were reading, and the with the invention of the printing press, more people were able to afford the mass-produced books than before as the books were painstakingly copied by hand.  Because more people were reading, new reading materials were created...magazines, newspapers...journalism as we know it was invented and thrived on its new audience.  The novel was also invented, and focused on the women of the time. It was a time of relative peace as the country had just come out of Civil War and plague.  They were reaching for change and rebelling against what had been.  There are many names for this time period...neolithic period, Augustan Age, Enlightenment, Age of Reason...all of which describe part of the era but none of which adequately represent the entire time.  Check out the links I've provided for more information.  Good Luck!