Depending on your current configuration, some of the abbreviations suggested in the examples may deliver different results.
Just use somewhat longer abbreviations in that case, e.g. type BOFOL instead of BF in order to select the "Bookmark Folders" category.
Note also that once you've trained shorter abbreviations for your favorite items you will be able to use these shortcuts as well and type things like
A<Space>NU
to search for “Network Utility” within the “Applications” category.