Question

I would like to ask regular ESS/R users what key bindings do they use frequently and tips on using ESS/R.

Answer 1

I have set several shortcuts in my .emacs file. The most useful are:

C-tab to switch between the R command line and the file (similar to josh answer, but much faster):

(global-set-key [C-tab] 'other-window)

Control and up/down arrow keys to search history with matching what you’ve already typed:

(define-key comint-mode-map [C-up] 'comint-previous-matching-input-from-input)
(define-key comint-mode-map [C-down] 'comint-next-matching-input-from-input)

Comment-uncomment a selected region with C-d or C-maj-d

(defun uncomment-region (beg end)
  "Like `comment-region' invoked with a C-u prefix arg."
  (interactive "r")
  (comment-region beg end -1))

(define-key ess-mode-map (kbd "C-d") 'comment-region)
(define-key ess-mode-map (kbd "C-S-d") 'uncomment-region)

Also I’ve also enabled CUA mode (from options menu) and reconfigured quite a lot of shortcuts to require only two keystrokes (instead of four in standard mode):

;; Delete selection when pressing [delete] key
  (delete-selection-mode t)

;; ESS Mode (.R file)
  (define-key ess-mode-map "\C-l" 'ess-eval-line-and-step)
  (define-key ess-mode-map "\C-p" 'ess-eval-function-or-paragraph-and-step)
  (define-key ess-mode-map "\C-r" 'ess-eval-region)

;; iESS Mode (R console)
  (define-key inferior-ess-mode-map "\C-u" 'comint-kill-input)
  (define-key inferior-ess-mode-map "\C-w" 'backward-kill-word)
  (define-key inferior-ess-mode-map "\C-a" 'comint-bol)
  (define-key inferior-ess-mode-map [home] 'comint-bol)

;; Comint Mode (R console as well)
  (define-key comint-mode-map "\C-e" 'comint-show-maximum-output)
  (define-key comint-mode-map "\C-r" 'comint-show-output)
  (define-key comint-mode-map "\C-o" 'comint-kill-output)

;; Search with C-f / C-F (control-maj-F for backware search)
   (global-set-key "\C-f" 'isearch-forward)
   (global-set-key (kbd "C-S-f") 'isearch-backward)
   (define-key isearch-mode-map "\C-f" 'isearch-repeat-forward)
   (define-key isearch-mode-map (kbd "C-S-f") 'isearch-repeat-backward)

;; Save with C-s / C-S
  (global-set-key (kbd "C-s") 'save-buffer)
  (global-set-key (kbd "C-S-s") 'write-file)
  ;; need to redefine them for isearch mode (don't know why)
  (define-key isearch-mode-map (kbd "C-s") 'save-buffer)
  (define-key isearch-mode-map (kbd "C-S-s") 'write-file)

;; Pause = dedicate window. 
  (defun toggle-current-window-dedication ()
   (interactive)
   (let* ((window    (selected-window))
          (dedicated (window-dedicated-p window)))
     (set-window-dedicated-p window (not dedicated))
     (message "Window %sdedicated to %s"
              (if dedicated "no longer " "")
              (buffer-name))))
  (global-set-key [pause] 'toggle-current-window-dedication)

;; delete = delete
  (global-set-key [delete] 'delete-char)

;; C-b = list buffers
  (global-set-key (kbd "C-b") 'bs-show)

You will find many more useful shortcuts in ESS documentation.