Here's a short reminder on what elements you have at your disposal:

----             Horizontal ruler
//               Forced line break
[link]           Create hyperlink to "link", where "link" can be either
                 an internal WikiName or an external link (http://)
[text|link]      Create a hyperlink where the link text is different from
                 the actual hyperlink link.
[text|wiki:link] Create a hyperlink where the link text is different from
                 the actual hyperlink link, and the hyperlink points to a
                 named Wiki. This supports interWiki linking.

*                Make a bulleted list (must be in first column). Use more (**) 
                 for deeper indentations.
#                Make a numbered list (must be in first column). Use more (##,
                 ###) for deeper indentations.

!, !!, !!!       Start a line with an exclamation mark (!) to make a heading. 
                 More exclamation marks mean bigger headings.

__text__         Makes text bold.
''text''         Makes text in italics (notice that these are single quotes 
                 ('))
{{text}}         Makes text in monospaced font.
;term:def        Defines 'term' with 'def'.  Use this with empty 'term' to                  
                 make short comments.

|text|more text| Makes a table. Double bars for a table heading.

A more detailed help

Avoid using HTML.

To embed images just put them available on the web using one of the approved formats, and they will get inlined automatically. To see the list of approved formats, go check SystemInfo.

To make a code block, use triple {'s to open, and triple }'s to close.

(Wondering where this text comes from? It's on a page called Edit Page Help, which you can edit too!)