By default, emacs has completion when you switch buffer. But you have to type the Tab ↹ key to see a list. It's rather cumbersome.
Enter icomplete-mode. It automatically display choices. However, you still have to press Tab ↹ to complete your name, then Enter ↵.
iswitchb-mode improves that. It automatically display choices, and you don't have to actually complete the name. When you see that the first choice displayed is what you want, just Enter ↵ and you are done.
ido-mode is even better. You can use arrow keys to navigate among all the choices. Also, the display of choices is more clear.
I was using iswitch in past years. ido is better. The major difference is this:
ido-mode will also show suggestions when opening a file (find-file).iswitchb-mode show suggestions, ido-mode show suggestion but also allows you to use arrow keys to navigate it.In short, ido saves you keystrokes.
Turn on ido-mode. But you should also have icomplete-mode on, because that also does describe-function and describe-variable but ido doesn't.
Added to: Tips on Long Term Emacs Productivity. See also: Emacs: Name Completion Features ＆ Packages
tips of using ido-mode with ErgoEmacs keybinding.
ido-find-file) will be called.find-file