To write in a clear and logical way, the first sentence of your paragraph should define what the rest of the paragraph will be discussing.
Tighter gun control or even the abolition of firearms would lead to a decrease in the number of deaths and injuries. This is because in many countries, access to this type of weapon is relatively easy, and this can cause incidents or accidents. For example, in the USA alone, accidental death from firearms accounts for over 1000 deaths per year.
Notice how the sentence in bold identifies what the paragraph relates to.
Here are some more topic sentences:
Reality television could be facing a revolt. Every night there is at least one on the television, more often two or three. Subjects can range from seeing a group of people living in a house together, with cameras watching them 24 hours a day, to more exotic locations where people, even celebrities, live on a deserted island and are required to complete certain tasks. While there is clearly a market for this kind of entertainment, there are a growing number of people who have become bored with this genre of programming and are refusing to watch, preferring instead to view other channels or even pursue other interests.
Computer viruses are becoming increasingly aggressive. Despite installing protective software, these threats continue to evolve, becoming increasingly sophisticated and damaging. This is an irritation to the home computer user, but is of far greater concern when they affect computers in government offices and banks, for example. In fact, it has been rumoured that certain software companies actively recruit the people responsible, thus turning the creation and implementation of viruses into something akin to a job interview.
The belief that we now have longer holidays is not always true. Take, for example, people working in the service industry. They are often required to work through what is traditionally considered to be the holiday period, and in many service industries, Christmas is one of their busiest times. Then there are people from the business world, constantly connected to their work through the Internet and mobile phones. The reality of the situation is that government legislation and laws regarding contracts have given us the impression of having more free time without actually reducing our workload.
An increasing number of women do not have to sacrifice their career in order to have a family. This is in part the result of legislation in favour of working mothers, in which companies are required to provide maternity pay to employees in the last stages of pregnancy and early motherhood. Returning to work is also facilitated by many of the larger companies providing crèches for younger children, meaning the parent is no longer housebound. There is also a trend towards having children later in life, once a career has been firmly established, or even not having children at all, giving the opportunity to follow career choices instead. A minor, and not yet substantial enough, role is also played by househusbands, men who take the responsibility for child care whilst the mother pursues her career.
Now practice! Read the paragraphs below and think of a suitable topic sentence for each one.
It provides an important release from the tensions of the workplace, allowing us an outlet for our energies in an increasingly hectic world. There is also the social aspect, as people often use their leisure time to interact with others in a society that is becoming arguably less sociable.
Traditional foods with better nutritional values are often overlooked as being time consuming and laborious and are often rejected in favour of more convenient options. Another reason that could account for this is the financial factor: the cost of a McDonald’s meal can often be considerably cheaper than a balanced and well-prepared meal cooked at home.
The clearest indication of this is the brevity of most e-mails. In a letter, we would never consider communicating with a single word or phrase, yet it is perfectly acceptable to do so using a computer. There is also the personal aspect: reliance on e-mail communication is undeniably distancing us from more direct contact, even the telephone. However, we cannot underestimate the convenience of e-mail, especially in situations which involve long-distance communication.