Almost everyone getting started in techical security how-to articles goes through their “securing SSH” phase. Hell, everyone has their handful of things to do when securing SSH. Usually these go from 3 suggestions up to maybe 7. This article at CyberCiti goes into 20 ways to run a more secure OpenSSH server.
Fine, some of them are suggestions that you certainly may opt not to deal with, but there is a pretty darn good amount of detail here to get started and feel good about SSH security.