First of all make sure the web design is user friendly meaning that the user shuold be able to access all parts of your website without any problems. Once you have made sure it is user friendly ensure that your layout is to a good standard, you want to have your highest priority of whatever you do near the top and then you want the stuff that is not so important near the bottom. it always helps if your web design is clean, I know it’s cool to have these personalized web designs with loads of graphics and what not but in truth all this does is slow down the speed of your website and having too much graphics can be a downfall meaning it won’t look that nice, if we look at today’s most popular website i.e. Facebook it has a nice clean web design with nothing over the top. Also please use an appropriate font, people don’t want to see a different font every time they go onto a different website they just want to be able to read it!!! Lastly ensure that your web design does not include too much flash this again slows down the speed of the website.
If you are getting your website designed by a graphic designer there’s no harm in checking out some of their old work to see if they include all of the above.
All in all web design can help improve your Google ranking so make sure it is up to standard.