Here we assume you are familiar with setting variables in Emacs, either thru 'customize' or in elisp (in your .emacs file). For a basic introduction to customize, elisp, and Emacs in general, see the tutorial in The GNU Emacs Manual.
These global Emacs settings are strongly recommended (put them in your .emacs):
(global-font-lock-mode t) (transient-mark-mode t)
‘(global-font-lock-mode t)’ turns on syntax highlighting for all buffers (it is off by default because it may be too slow for some machines).
‘(transient-mark-mode t)’ highlights selected text.
See the Emacs help for each of these variables for more information.