I've found Vim shortcuts to be a game-changer for efficiency. To select all text in Vim, you can use the command 'ggVG'. Here's how it works: 'gg' moves the cursor to the start of the file, 'V' enters visual line mode, and 'G' jumps to the end of the file, selecting everything in between. For deleting, once you've selected all, simply hit 'd' to delete the entire content.
Another approach is using '%' which represents the entire file. Typing ':%d' will delete everything without needing to select first. These shortcuts might seem arcane at first, but once you get used to them, they become second nature. I also recommend pairing these with other Vim commands like 'u' for undo and 'Ctrl+r' for redo to make your editing workflow even smoother. Mastering these can save you countless hours over time.