Para 1: state the topic
Para 2: advantages and justifications/examples (There are certain advantages to travelling by bus, by car, by train, by plane. Firstly, … . Also, … .)
Para 3: disadvantages and justifications/examples ( On the other hand, there are certain drawbacks to travelling by bus, by car, by train, by plane. First of all, … .Secondly, … .)
Para 4: your opinion (To sum up, … .Although …, they are … .)