<C-N><C-P> : word completion in insert mode
<C-X><C-L> : Line complete SUPER USEFUL
/<C-R><C-W> : Pull <cword> onto search/command line
/<C-R><C-A> : Pull <CWORD> onto search/command line

<C-X><C-E>,<C-X><C-Y> : scroll while staying put in insert

 

open new tab page and edit {file}, like with :edit
:tabnew [++option] [+cmd] {file}

close current tab page
:tabc[lose][!]

go to other tab page

gt

go to previous tab page

gT