Firefox has this amazingly useful but hidden feature of adding shortcut for a bookmark. This is not just restricted to search based urls. Here is how to do this.

1. Bookmark your favorite URL
2. Go to Bookmarks -> Organize Bookmarks… menu
3. Choose the bookmark from (1)
4. In the bottom panel, click on “More”
5. Enter shortcut word or letter in “Keyword” text box
6. Close “Organize Bookmarks” window
7. In the address bar, type the word or letter from (5)
8. Viola!
9. Enjoy the time saved in taking the mouse pointer to Bookmarks menu and selecting the bookmark 🙂