When you have to talk about a topic, you can arrange your ideas around advantages and disadvantages. Most things have cons and pros.

Divide your talk into four parts:

1. Give the topic you are going to talk about and state that you are going to mention some of the advantages and disadvantages.

2. Talk about the advantages

3. Talk about disadvantages

4. Give your opinion

Example:

Television

As far as I know television was invented in the 1920s or 1930s and has become an important part of our lives since then. Like everything else in life, it has advantages and disadvantages.

First, let me speak about the benefits of watching television.

I have a nine-to-five job, I usually arrive home between 6 and 7 pm. I am very tired in the evenings, so I just want to put up my feet and relax. I am not very fond of going out, I prefer watching TV to going to the cinema.

A second point is that TV is very entertaining. I am fond of comedies, they really cheer me up after a hard day at the office. I have cable TV and I subscribe to comedy channels.

In addition to this, TV brings the world into my living room. It gives me information about the news and the weather and many other things.

Last but not least, watching American films with subtitles is a great way of learning English.

However, there are disadvantages, too.

Firstly, I am short-sighted and watching TV is not too good for my eyes.

Secondly, if you watch too much TV, you will become a couch potato.

Also, you can become more isolated and lonely if you watch TV instead of going out.

Another point is that sometimes I get fed up with TV programs like reality shows or violent films.

Overall, I think that despite the disadvantages, TV is one of the best inventions ever. You just have to enjoy it in moderation and be very selective.