Very often I am asked to SSH to a machine just to hit access denied. A few roundtrips then needed until issue is resolved. Here are my commands to get it working from the first time.
# mkdir .ssh
# vi .ssh/authorized_keys # add user's public key here
# chown -R user.user .ssh
# chmod 700 .ssh
# chmod 600 .ssh/authorized_keys
# restorecon -R .ssh