Use the desktop library to save the state of Emacs from one session to another. Once you save the Emacs desktop—the buffers, their file names, major modes, buffer positions, and so on—then subsequent Emacs sessions reload the saved desktop. By default, the desktop also tries to save the frame and window configuration. To disable this, set desktop-restore-frames to nil. (See that variable’s documentation for some related options that you can customize to fine-tune this behavior.)

If you are using Prelude you can just use C-c s (prelude-swap-windows). From the Prelude documentation:

C-c s runs the command crux-swap-windows (found in prelude-mode-map),
which is an alias for crux-transpose-windows in crux.el.

This document describes a set of features that can interactively do things with buffers and files. All the features are described here in detail.

The Ido package can let you switch between buffers and visit files and directories with a minimum of keystrokes. It is a superset of Iswitchb, the interactive buffer switching package by Stephen Eglen.