Web Development

The content (text, images, Flash movies, etc.) is the most important element in web design and it determines the layout, the number of pages, and the download time. A website should have a good appearance and functionality on all browsers. This is not easy to achieve, there are differences in how various browsers interpret style sheets and client-side scripts, in the default size of the browser window or the screen resolution.
Web standards are a wide collection of rules and concepts, continuously discussed and improved by the web community, concerning optimal use of XHTML/HTML and style sheets specifications, and other tools like JavaScript and CGI scripts, Flash, etc. for efficient and accessible websites. The main rule is to write valid XHTML/HTML and CSS code following the W3C recommendations. A correctly and well designed website is also search engine friendly and can get good results for search engine queries.

Page structure

It is important to have a well structured document, where the HTML elements reflect the content. Correctly nested header elements (h2 after h1, h3 after h2 etc.) should indicate the content structure and should not be used for formatting text, navigation blocks should be implemented by lists, tables should be used for presentation of meaningful correlated data and not for page layout.

Page layout/visual rendering

The concepts for good web design lead to better content accessibility, i.e. using tables only to present data (not for layout), and separating style information for page layout or formatting from the HTML code to style sheets. Many attributes of HTML elements that specify layout or formatting (like the background, text, link, vlink, alink attributes of the body element, the bgcolor, align, width, height attributes of many HTML elements, the center, font, basefont elements) are deprecated in the HTML 4.01 Specification, that recommends the use of style sheets instead.
It is better if the font-size is not set in absolute length units, so that the user can change the font size if necessary (by using the browser's 'Text Size' feature, or personalized stylesheets etc.).

Media-specific styles

Style sheets can be used to present a page differently to different media (computer screen, printer, Braille device, speech synthesizer, etc.) by using the @media or @import rules, or the media attribute of the style element. When printing background images should be left out, links text does not have to be underlined, browsers like Mozilla have problems printing large float elements, etc. There are some excellent articles by Eric Meyer about alternate-media stylesheets, like Going to Print and Print Different.

Web security

There are complex web security issues, but a simple question is how to defend a site from bad robots searching the web for server-side scripts that send e-mail, add links to a page, implement blogs and message boards, not to mention online money transactions or e-commerce. There are sophisticated ways to deal with that, but to protect simple scripts there are relatively simple things like checking the domain of the web page from where the script is accessed, logging the IP address of the computer accessing it, restricting access to scripts, limiting the size of information transferred via online forms, controlling file upload via online forms, etc. Sometimes online forms have an extra field to be filled-in with a given string of alpha-numeric characters, to stop access to spam robots.

Cookies

Many websites send cookies (very small text files) to a visitor's computer hard drive to record various information, usually harmless and sometimes necessary in implementing a consistent and secure flow of online data transfer, but that nevertheless can raise privacy concerns. AboutCookies.org is a website that gives information on cookies and on UK guidelines and laws regarding cookies.

Favicons

Favicons (short for 'favorite icon') are a detail in website design, but I think an important one. They appear on some browsers in the top URL bar and also, if the site is bookmarked, in the bookmarks window, together with the site's URL. A favicon is an image file named favicon.ico, located at the website's root directory, usually 16x16 pixels, in a special format that adapts to the browser. There are websites with online free favicon generators, like www.favicon.co.uk. There is a very good favicon presentation at en.wikipedia.org.

www.w3.org/TR/
W3C Technical Reports and Publications
www.w3.org/MarkUp/
W3C HTML Home Page
www.w3.org/QA/Tips/
W3C Quality Tips for Webmasters
www.w3.org/2001/tag/doc/contentPresentation-26.html
W3C Separation of semantic and presentational markup
validator.w3.org/checklink
W3C Link Checker
www.google.com/webmasters/guidelines.html
Google Webmaster Guidelines
buzzword.org.uk/colours
colour calculator by Toby Inkster
www.webstandards.org/
The Web Standards Project
www.w3.org/Security/Faq/
Web Security FAQs
www.arcray.net/resources/
Arcray Webmedia - Internet Related Articles