Poor Web Design Decisions
There is a lot of information out there on how to set up a better web design. Some of that information is available on this site. But it is also important to know what should be avoided to ensure your web design is not bad. Some elements of web design have fallen out of favour; others have fallen way out of favour.
The first thing, probably considered no more than a mild web design faux-pas, is the sudden presence of a PDF download on a website. While PDFs were, and still are, a useful way to view documents, they also rely on the user having a PDF reader, and a fairly large download to boot. From a web design perspective, they break up the experience. If at all possible, you should try to synthesize the information from the PDF on a regular page, so that the web design is the same, and the experience is consistent. Sometimes using PDFs can even result in a browser crash, something no web designer wants to cause.
A more egregious error in web design is poor colour selection. Selecting the colour of text in relation to background is an area where you must take care when creating a web design. Even though some colours might look good together, and fit your aesthetic nicely—like white and light blue, for example—having white text on a light blue background is a bad web design choice. While the text will still be readable, it will be very difficult to do, and no visitor is going to be happy with your web design. Instead, keep the contrast between text and background high in order to make reading text easier with your web design. A web design that is easy to read and navigate will foster a familiar comfort in your users expereince.
The most ridiculously bad web design decision is the Flash-based welcome screen. Most people know what this is, and nearly everyone despises it. You open up a website, and after waiting for 15 seconds for something to load, you are suddenly overwhelmed by a loud video that lets you know you have arrived at this website. This web design move was en vogue 5 or 10 years ago, but is now just poor form. This web design is crass and unwanted, because it dramatically slows loading while simultaneously hitting the user with an unrequested blast of aural and visual stimulation. The only reason to use this in your web design is if you, for some strange reason, want people to absolutely despise your site.
Avoiding these three web design decisions will ensure your website is not universally hated. If you are really set on using PDFs, that is excusable, but somewhat understandable. However, no one will appreciate your web design including either difficult-to-read text or a Flash intro; those will send people to another page as fast as they can press the back button. Instead, use high contrast fonts in your web design, and avoid Flash if possible.