"Mangiamo la carne."
There are a few hints, but frankly you're better off just memorizing the word with the article. ie. Don't learn it as carne = meat, learn it as "la carne" = "the meat"
Seriously, this will serve you well.
But here's a few links with some hints anyway: http://italian.about.com/library/weekly/aa051000a.htm http://italian.about.com/od/grammar/a/gender-of-italian-nouns.htm