1. Have a good communication with your client
On one occasion I attended a person who wanted a Soft Eyeliner with a brown color and looked as natural as possible. For this, I made an eyelash enhancement and applied the color Cafe Olé. A month later she returned for the touchup saying that she wanted the eyeliner thicker and darker. I made a thicker eyeliner and applied the color Earth. A month later, I received a call from her saying that she wanted a new touch-up because she wanted the eyeliner even thicker and darker. At that moment I used Mahogany and made a really thick eyeliner.
I was not happy and talked to her explaining that what she had asked me initially was something very soft and natural and what I had done that day was something that I did not consider soft and natural, and she answered: This is what I wanted. If you don't want to go through situations like this, it’s important that you understand what your customer wants and what is the best effect for her.
On the other hand, you need to properly explain the difference between the effects that you offer: Individual hair strokes vs. Eyebrow Shading vs. Solid Eyebrows, and
Eyelash Enhancement vs. Thin-Eyeliner vs. Thick-Eyeliner.