Resources online abound. Weeding through it all, knowing what's good and what isn't is the trouble. Years ago I learned Fournets for better searching. Talk about a skill you want everyone to have. It's indispensable.
I also use WordReference.com extensively: their translation bookmarklets, customized searches and app on my mobile devices.
I can go directly to these dictionaries English-Italian, Italian-English, and Dizionario Italiano, and then their Wordreference Forums, a wonderfully engaged community, linked right on the dictionary page.
I also use Treccani l'enciclopedia italiana, an Italian resource.
That's how I'm learning Italian.