Use emacsclient and have a emacs server running at all times. Super fast startup times, you can even use emacsclient -nw (or make an alias 'e' for that) in the terminal for fast edits with instantaneous startup.

You could also make a script that starts emacs as a client only if a server already is running

  #!/bin/sh
  if [ "$#" -eq 0 ]
  then
    echo "Starting new Emacs process ..." >&2
    nohup emacs > /dev/null 2>&1 &
  elif emacsclient -n "$@" 2> /dev/null
  then
    echo "Opened $@ in Emacs server" >&2
  else
    echo "Opening $@ in a new Emacs process ..." >&2
    nohup emacs "$@" > /dev/null 2>&1 &
  fi

(Copied from an emacs starter kit but don't remember which...)