I've come and gone with various vim config changes, but this is the one non-standard one I've stuck with:

au! BufRead,BufNewFile * lcd %:p:h

This makes it so that when you open a buffer, you cd to the current directory (only for that window), so you can quickly open files in that directory.

[% is the current file relative to pwd, :p converts to a full path, :h takes off a path component, lcd does a cd but only for the current window]

Another tip is that when your internet connection sucks enough for SSH lag (tethered, free wifi, whatever), you can edit a file locally and have vim do the SCP back when you write:

:e scp://you@somewhere/path

Boom!