GUI evaluation practices?

Hi there,

I'm trying to evaluate a system for studying RDF documents, mainly
vocabularies and ontologies. I'm not sure if there are best practices,
guidelines or any other information that may be related to visualizing RDF
graphs (or graphs in general). Any pointer?

Thanks in advance!

Alvaro Graves-Fuenzalida, PhD
Web: http://graves.cl - Twitter: @alvarograves