The Meta Tag settings on your Joomla website include:
Global Meta Tags
Global Meta Tags are used on all the pages that do not have individual settings. They are set in the Global Configuration area of your website and therefore you may need to ask your website designer to change them for you.
Article Meta Tags
Each article can have different meta tags, log in to your article and enter your chosen text in the Metadata Information panel. Any fields you leave blank will use the settings in the Global Meta Tags
Only use words/phrases that are visible on the relevant page, if your page says 'We make purple hand-widgets' the phrase 'purple hand-widgets' will be found to be relevant whereas 'purple widgets' will not. Try to position your most important words/phrases as close to the begining of the tag as possible.
|Description Meta Tag:||Google uses 156 characters, Yahoo 250|
|Format: Write as a sentence putting your most important information first|
|Keywords Meta Tag:||10 or less is good, fewer words have more weight.|
Format: Write as a list separated by commas, putting most importan first eg:
purple widget, strong widgets, widgets for sale, hull widgets, online widgets
Analyse your Meta Tags
This useful tool from SEOCento will help you analyse your tags