Optimize anchor text
Optimizing your anchor text (the words you click on that make up a link) is extremely important, especially for your own internal URLs. When building an internal link structure, this is the most important issue to look at. Instead of using an anchor text like Click here, you should use something more descriptive, like Joomla Caching (if the article is about caching). This provides meaning and context to the URL you are pointing at. You can easily arrange this in your editor. If you use your editor, like JCE, it is very easy to set a good anchor text. And it is sometimes hard to get it right. Even here on my own site, I often use the "click here", even though I shouldn't....
You can easily arrange this in most editors. If you use your editor, like JCE, it is very easy to set a good anchor text.
Note that for images that are purely used for decorative purposes, without any contextual meaning for the page, it is advised to leave the alt-text empty.
There can also be situations where you just have to use a non-descriptive anchor text. This can be due to space limitations or whatever. In cases like that, you can make use of the title attribute to enter something more descriptive. This gives meaning to both search engines and disabled people. You can usually enter the title attribute with your editor (see the JCE screenshot above) or simply add it into your HTML, like this example:
<a href="#" title="Download section with Joomla plugins">Downloads</a>
Note that especially your menu items are often very short, and sometimes not that descriptive. You can then use the Link Type tab in your menu items to add this description:
Note that in most cases, supplying a title attribute is not necessary.
Incoming links from external sites
Once your site is live and you are ready for your linkbuilding activities, keep this practice in mind as well, it is also important there. However, you should also keep in mind that your site remains a natural link profile, which is normally a profile where about 70% of the anchor texts simply show the bare URL. A link profile where the anchor text from external links is primarily built with your desired keywords is a possible signal for buying links, which can get you penalized.