This is mostly for convenience but may be necessary if you are having problems using sshfs.

Rather than having to type something like:

ssh -i .ssh/myidentityfile.pem ubuntu@my_ec2_ip

You can create ssh shortcuts to simplify this to the following:

ssh myec2

To do so, create the file .ssh/config (if it doesn't already exist) using this template:

Host your_shortcut_name_here
    HostName      your_ec2_ip_address_here
    IdentityFile  /home/ubuntu/.ssh/myidentityfile.pem
    User          ubuntu