Welcome to the forum and good luck on your exam!
You've got a lot of really good things in your essay, the vocabulary is very nice. I've just highlighted some of the phrases that I like.
The one area that you should try to improve is clearly answering the question. The paragraph about Ah Huat coffee isn't really relevant the way it is written now. Is it about people buying things they don't need? Is it about advertisements telling us about new products that improve our lives? No. So you can leave it out. Try to make little notes before you start writing so you are sure that you are focusing on the question.
- Introduction: paraphrase the question
- Advertising tells us about products
- another example?
- Advertising makes us buy things we don't need
- example 1
- example 2
- Conclusion: here is my opinion
You can see from my notes that I think you need examples of advertising making us buy things we don't need. In your conclusion, you state your opinion but then you weaken it with your last sentence. A stronger conclusion would be to make the opposing point first and then finish with your own opinion: "Obviously, consumers need to research products carefully and spend their money wisely. But in conclusion, I feel that advertising helps people be aware of the latest product developments and assists them in decision making when there are many choices for in the same range."
When is your exam?
If you have any more questions about IELTS, you can post them here or read the strategy guide I have written on my website: Part 3: Writing | Ben Teaches English
Good luck on exam day!