I use the fish shell. In fish, you can just add fish_vi_key_bindings to your config file and now Vi bindings will be automatically enabled when you start fish. For bash, it’s set -o vi and for zsh it’s bindkey -v. For the browser, you can install plugins like Vimium (Vimium-FF for Firefox) or Tridactyl. I find these to be incredibly useful, I love navigating around websites with j and k or d and u, jumping up with gg and down with G, searching with /, closing tabs with x, reloading websites with r, opening new tabs with t, going back and forward with H and L, etc.