Masculine and feminine in French - how do you know which one to use?

Over the last 10 years teaching French to adults I have seen and heard a lot of tactics for dealing with one of the biggest challenges we face when speaking French. That challenge is how to decide if a word is masculine or feminine?

One popular tactic is to say that every word ending in “e” is feminine (la). But there are far too many words that end in “e” that turn out to be masculine, making this approach difficult to use with any degree of accuracy. Another is to try to assign an actual gender to an object. So women wear dresses so “une robe” but where do you go when the word for shirt is “une chemise” and the word for beard is “une barbe”?

 Hold on all those words end in “e” and are feminine. That rule does work! Well it does for some but what about “un risque”, “un geste”, ” un casque”, “un degré” and so on. 

Of course you could just hedge your bets and begin a sentence by calling a house “une maison” and finish the sentence by referring to it as “un maison” succeeding in covering both bases and being right 50% of the time! But that sounds like too much hard work plus never really knowing if you got the right gender for a word isn’t very satisfying.