1. Framed web sites - These were a good idea once, or so a few people tell us! There are, or at least were, a number of reasons for designing sites in frames. But stay away from them at all costs. You can have a global navigation in an include file, so that excuse has gone. If you want to include something for instance a third party form you could use an iframe on the relevant page. But there is no need to frame an entire website - it makes it harder for search engines to crawl your web site and traffic cannot bookmark your pages.
2. Not testing on different browsers & screens - As the internet develops and moves on, so does people’s choice of browser. Yes, based on my own research probably about half the world users some form of Internet Explorer, but a third use Firefox. And if you merely test on one version of Internet Explorer your web site may not work on other versions, or fail on Firefox or other browsers. The same goes for developing in a widescreen screen and ignoring the majority of the population on smaller screens.
3. Masses of flash, lots of colour, plenty of movement - It might be clever and take a lot of time, but the finished result looks in excess of the top, amateurish and very off putting. As tempting as falling snowflakes and a mouse trailing shooting stars may seem, avoid them as they went out years ago.
4. Forget splash pages - Why do you think your visitors want to sit through an introductory page every time that they decide to visit your website? Do they really want to sit through a 10 minute presentation of why you are the best in your field, with a ball bouncing around the screen to explode the reasons out of nowhere? Again, it is far too clever and time consuming and has a negative effect. Merely get your customers straight to where they want to be - remember you have seconds to impress them, not minutes.
5. In excess of optimise a website through putting every keyword in bold, underlined and italic - Using every bit of emphasis that you can does not alert the search engines to the fact that these are the correct search terms for your site, instead it alerts them to the fact that you are over optimising. And by poor use of these techniques the page becomes unreadable. Instead, use these features to highlight key areas and titles to help readers find their way through your website.
6. Forget to read and test your web site - A reader will not like reading a page that is full of real clangers of spelling mistakes that stand out a mile or a page in which several of the links when clicked on produce error pages. Be certain that that everything is correctly spelled and that all links are working.
7. Clashing colours and over the top backgrounds - They might be eyecatching and grab attention, but backgrounds that compete with the main area of the site distract attention and clashing or too a lot of colours are equally distracting.