In web designing, you are going to use your creativity plus your skills in HTML/CSS WordPress skills and many more. You are suppose to design like you are designing a piece. Just as a human body has complete parts, website also has a complete parts namely header, body, sidebar, footer. These are the major parts of a website theme. Designing these is just piece of cake in WordPress, you do not need to worry about how things will work out if you know how to manipulate each and every part of the theme.
The header contains the stimulant of the body, which means, the header contains the title, of the website, banner, navigation bar and links if necessary. The header catches the attention of visitors so it makes sense to make the header part beautiful.
The body is the main content of the whole website, this is why the visitors were directed to the website because they are looking for something from this part. For intelligent readers, they look into the beautiful body, not the head. This is why page and content pages must be the most important.
The Sidebar is like the arm of the body, so you see this at the sides of the pages. It adds sense to the body and is really a helping hand to the body. You can also make the sidebar beautiful to make a website alive.
Footer is where you put additional information at the bottom of the website, you can put here additional readings or whatever. If you put footer is ugly to look at, it is better to omit it. But if the footer looks alive matching with all parts of the body, then be inspired to put some.
In designing a website, graphic designing is necessary for beautiful and amazing appearance of the site.