Another great article Caroline, well done! 

One thing though, I'm not sure to understand the 3-a rule. While I understand we'd always say "Il est allé" and "Il est revenu", I think some of these verbs can be used either with être or avoir depending on the meaning: 

 - Il est descendu en bas / Il a descendu les marches (applies for monter too)

 - Il est rentré chez lui / Il a rentré sa voiture

 - Il est retourné travailler / Il a retourné sa veste 

Did I miss something?

Anyway, I think people should definitly learn words with "un/une" to help them remember, just like you said. When a foreigner gets it wrong it's kinda "cute" though, but it has to be occasional ;-)

Oussama, I know! my Russian students mentionned the same "problem" in Russian. Are the German genders the same as the French ones? In Russians, 50% genders are not the same as the French ones, so on top of having to learn new words like "table" they have to forget it was masculine in their language and get used to say "une table" (which annoys them no end). I heard "UN salade", "UNE rêve" and so on almost every day!

You find genders in French to be hard? Try the German language , with maskulinum , femininum and neutrum. :)

Thanks for the great explanations Caroline! I am teaching myself French for the first time and all of your articles are very heplful!

Thanks for the clarification Caroline :)

I'm doing Russian at the moment, and they do have some rules to know if it's masculine / feminine / neuter: for example endings in а or я means the word feminine. They have exceptions of course but I <em>think</em> it's easier to guess the gender.