The design is, after informative, quality-rich content and ease of use, an important part of your website. A poor design can lead visitors to simply browse on to another site that appeals to them better visually.
It's not always that you know what you want your website to look like, and then it becomes a process where I present a design that is then customized until it becomes the way you want it. A big help then, is if you have seen some web pages that you find visually appealing, that can be used as a starting point, or come with wishes in relation to design.
Design always gets a little back and forth before landing on the right thing, but here, too, it's important to be realistic in terms of how much back and forth it can be, before the price rises. Therefore, it is important that you have a certain idea in advance of what you want, so that the design does not have to be changed again and again.
As a rule, I ask you to approve the design before I go ahead and build the rest of the website. Small changes and tweaks are fine, but if you want a completely new design further in the process, it will cost a little extra. Think of it like having a painter paint your house pink. Once he has painted two sides of the house pink, you can't change your mind and ask him to paint it blue instead, at no additional cost. Then you would be left with two pink walls, two unpainted and only see the back of a very offended painter.
So a little advance research might be a good idea: