We have to be fair on both sides. Clients do end up paying for bad work and not all designers are good and skilled.

First of all, know your quality. If you are good, you will be able to understand the client's needs and able to get what they client wants. This will cut down your time and the client's time.

Charge according to the work & client. Don't expect to charge high fees on small unknown brand.

Some guidelines:-

Concept (ideas driven with clear messaging) - this one can charge more - approx RM500 - RM800 per day (8 hours)
Design - approx RM350 per day (8 hours)
Visual - approx RM250 per day (8 hours)
Final Artwork - approx RM100 - RM150

A brochure design will have more design and FA hours while print ads will have more concept hours. When you are adapting work from bunting to poster, you charge FA price.
If you are 4As agency and have hundred thousands of staffs, of cos you charge more to the client. Cannot compare.