The first method is to make sure the typography of your content is suitable. If you have large blocks of text, make sure to use CSS to space out the lines accordingly. The longer a single line of text is, the greater the line-height of each line should be. Also, make sure the font size of your text is big enough to read easily. Some sites have 10-pixel-tall text in Verdana font; while that may look neat and tidy, you have to really strain your eyes to read the actual text.
Make it easy for visitors to find content that they want on your site. If you have thousands of articles on your site and a certain visitor wants to find one single article from that pile, you have to provide a feasible means to enable visitors to do that without hassle. Be it an SQL-driven database search engine or just a glossary or index of articles that you have, providing such a feature will make sure your visitors can use your site with ease.
Ensure that your site loads fast if you do not want to lose visitors. Most internet users will leave a website if it doesn't load completely within 15 seconds, so make sure the crème de la crème of your website is delivered to the visitors as soon as possible to retain their attention.
Last of all, test each and every link on your site before it goes online. There is nothing more effective in tarnishing your professional image than broken links, so be very careful about that.