Five Gmail tips and tricks. Number one. Click on the settings gear and then view all themes. Scroll down a little bit and select dark as your theme. This looks so much better! Number two. Press the shift key together with the question mark key. This opens up all of the available shortcut keys. My personal favorite, press the C key to compose a new message. Number three. Click on the search options icon and here you can search for all messages greater than 10 megabytes. You can delete these if you need to free up space in your Gmail. Number four. Click on the settings gear, then see all settings. You can set undo send up to 30 seconds. This way if you send a message, you can undo send it. Number five. Within settings, click on offline, check this box, and you can make Gmail available even when you have no internet access.