As has been mentioned, the big thing you want to look at is what are the sources of the author's information. If a site doesn't list any sources, I'd be wary - most legit sites will list where they got their info from. If you aren't sure, sometimes you can also google a key sentence or two from the article/site, and find the source easily enough. You want to look for scholarly texts/research, historical reference texts, source myths/lore. You can also look up information on the author, to see what their credentials are.
The article you linked (is from a general Pagan "newspaper" that is no longer being published) so how good the article is, would greatly depend on what sort of submission standards they had. The author isn't really making any claims of fact, it's looks like it's just their take on where a person who is new to Hellenic Recon should start if they are interested. I did notice that a lot of the "resources" listed all go to the same site which is never a good thing, but in general it's always a good idea to cross reference any article with other sites/sources.
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Somewhat off-topic, but if you are looking specifically for Hellenic myths/lore and recon info...
source text list,
other links of interest, and
Sacret Texts also has quite a few source texts (some of them may be the same as linked above).
This
forum seems to be fairly active and could probably point you in a good direction as well to actual Recon practices, and there is always the
e-Cauldron Hellenic page (though that one should definitely be cross checked with other sources).