Beginners sometimes ask "What should I collect?" Our members have been generous with good advice. Actually, I'm not sure a beginner can do much better than to watch threads for a while and get a feeling for what they like.
However, they might wonder about reference works. I have been assembling pages of sale-catalog references organized by collecting theme for many years. I finally decided to improve those theme pages by including relevant books. To link the themes together I created this web page
http://augustuscoins.com/ed/catalogs/themes.htmlwith two goals:
1) Give beginners an idea of the wide variety of ancient coins and potential collection themes.
2) List reference works collectors could consult to learn more, or much more, about those themes.
I hope to improve those reference pages (I solicit your suggestions).
For example, one theme might be "specific victories":

Denarius of Marcus Aurelius (AD 141-161-180) citing his Sarmatian victory with "DE SARM" in exergue and the date TRP XXXI = 176/7. A pile of arms from the defeated foe.
Here is one more piece of advice. If you have some idea of what you might collect (maybe by viewing my page, or reading a thread) that you can describe in words, enter those words in the search engine (in the bar of links near the top of this page) and see what has been shown and written using those terms.
My main page for beginners of "Frequently Asked Questions":
http://augustuscoins.com/ed/numisand my main educational site:
http://augustuscoins.com/ed/which has a page of links to other sites.
I invite you to post your advice for beginners on this thread.