It would be nice if you could create a vector from your current location on the map. This would make it easier to project a waypoint using triangulation. For example enter a bearing from your current location to a landmark and create the vector. Then move to a new location and repeat the process. The intersection of the two vectors would be a good approximation of the landmarks location. A waypoint could then be created at that location.
An addition to this tool that would be nice is concentric user defined incremental range circles centered on a location. This would also make waypoint projections easier.