Here are a few of the most useful SharePoint shortcuts, which work in all versions of SharePoint 2007 and 2010 (even 2003).
Enter page web part maintenance mode
?contents=1 to the URL of the page for which you want to enter maintenance mode, for example:
Enter page edit mode
Including system pages, such as view or edit pages: NewForm.aspx, EditForm.aspx, AllItems.aspx, etc.
In Internet Explorer’s URL bar type:
For more details on ShowToolPane parameter, you can refer to this old MSDN article.
Heads up: There is one thing you must seriously consider before editing a system page. This lesson I learnt the hard way from exposing modified edit pages to end-users. When you modify a previously read-only system page, such as a view or edit form, through the shortcut explain above, you make it available for editing to anyone who has contribute rights on that library or list. Hence that page becomes vulnerable to accidental changes by non-power users, because previously hidden Edit Page menu will be visible to them in Site Actions menu.
Access administration pages
A few quick shortcuts that I find not only can save time, but also help bypass obscurity created by system administrators:
http://site/_layouts/savetmpl.aspx – Save site as a template
http://site/_layouts/create.aspx – Create (libraries, lists, pages, sites)
http://site/_layouts/settings.aspx – Site settings
http://site/_layouts/newsbweb.aspx – Create a new site or workspace
http://site/_layouts/sitemanager.aspx – Site content and structure browser