Only give your own opinion when it is asked for. Actually, out of the 6 main types of questions that get asked in the test, only one does not ask for your opinion at all. That is a two-question essay. Something like What are the problems? What are the solutions?
With this type of question, you do not give your opinion at all. Read model answers for the 6 types of questions here:
Different Types of IELTS Essays