Exact phrase search: enclose the phrase in double quotes, not single quotes. (MOS no longer supports NOT keyword search; e.g., the old syntax -rdb to exclude documents with rdb no longer works. MOS no longer supports AND operator; documents with both or all keywords are shown before those with any keyword.)
Search page You may bookmark this: https://support.oracle.com/epmos/faces/KMConsolidatedSearch (Right click the link here and choose "Bookmark This Link" or "Add to Favorites".) (Ref)
SR page for mobile phone: https://support.oracle.mobi Fast, easy to login, but quick timeout
Status codes for bugs are documented on various web sites, such as this page, or officially and more completely at Service Requests document.
You can't search text within your SRs. Follow this article to download them, index on your local computer with a desktop search engine, or index and share them with coworkers with Sharepoint. (Update 2012-02: the code in that article needs serious update)
HTML MOS has 60 minute idle timeout for the browser. Use Check4Change add-on for Firefox and set the reload to any time shorter than that, e.g. 59 minutes. (thanks to Rich Jesse)
How to get Oracle Support the cheapest way There're two easy ways. For consultants, you can ask the company you're helping to solve a problem that they add you to their MOS account list. Technically, once you're done with the help or consulting work, your account should be removed. But they may be willing to keep you on the list either for being nice or expecting your help soon. Another way is to buy a very cheap Oracle product for a few dollars. (credit to Jeremiah Wilton)
[Update 2016-01]