The following is something I didn't know about until I began digging into WordPress. It is shall be my first pro tip:
WordPress dynamically generates some of its action hooks. Such hooks are referenced in the action reference section of the codex but it's easy to miss their existence (at least I did, at first).
And do a Ctrl+F/Cmd+F for "-("
The bit inside the parens is what gets dynamically generated.
The stock example given in the codex uses the "adminhead-(pluginpage)" hook: http://goo.gl/EeEsP
Important note: For this hook and some others the codex says "or" in the following fashion: adminhead-(pagehook) or adminhead-(pluginpage). This is because page_hook was deprecated.
Such dynamic hooks are useful because they let you bind actions that run only on certain pages. However, only a subset of hooks are generated this way; there is no adminnotices-(pluginpage), only admin_notices.
In such instances just wrap the code in an if statement and test against the $pagenow global variable or the newer (since 3.0) getcurrentscreen() [http://goo.gl/VxeIp].