The problem is that there is a big gap between domainers and end users, 90% of monthly sales are domains recycled between domainers themselves!
If domains were like products that people buy on Amazon then they would sell like candy. The problem is that end users are not aware about the domains for sale out there, unless they are in the moment of typing a domain name inside Godaddy search bar, only in this narrow time frame there is a small chance that your domain will be found.
You need to try all methods mentioned above plus try promoting on social networks. and maybe do some outbound.