With the newest redesign of the search results pages, Google made it more difficult to use most of the keyboard shortcuts that permitted you to quickly select a result or see a small preview.
Until now, you might type your query, press Enter to hide the list of suggestions and press Enter once again to go to the first result. If you didn't like the first result, you might press the down arrow to select the second result. Google also incorporated a keyboard shortcut for Instant Previews: the right arrow. None of these shortcuts are obtainable in the latest interface, at least not by default. Now you need to press Tab after performing a search to allow the old keyboard shortcuts.
Here's a search results page after typing a doubt (notice that there's no arrow next to the first result):
Here's what happens when you press Tab (you can use the up/down arrows, but the shortcut for Instant Previews no longer works
Google most likely disabled these features because not many people used them and a lot of users complained that the shortcuts made routing more difficult. Power users need to learn that Tab enables keyboard shortcuts, but having to allow the feature every time you use Google Search is annoying. After all, shortcuts were supposed to make your life easier and help you be more creative.
Google Instant shortcuts are still obtainable. You can continue to use the up/down arrows to select a different look for suggestion, the right arrow to visit the first result for the search suggestion, Tab to use Google's suggestion and continue to type your query, Esc to choose the query so you can quickly overwrite it.