Located in ~/.vimrc

If it doesn’t exist, create it!

set smartindent
set tabstop=2
set shiftwidth=2
set expandtab

"enables mouse in all modes. supports click and scrollwheel. use shift+ins to paste from clipboard
set mouse=a

"for use with pathogen
syntax enable
filetype plugin indent on

"for use with solarized. may require export TERM=xterm-256color
set background=dark
colorscheme solarized

To see more info on these settings, from within vim:

:help smartindent

To format a file with mixed tabs and spaces, after applying the above settings, from within vim:

:%retab