I'm always on you all about agreement, not just because I believe we should all be agreeable, but more so (!) because French agreement is a redundancy feature in the language that supplies you with additional information so you can know who is doing what to whom and to what. As we ALL know by now, French 'drops' a lot of sounds in pronunciation; some of the agreement issues make up for the lost sounds.
So, like what? Like articles (le/la/les/l'--un/e/des/de/d'--du/de la/de l'/des/de/d') & adjectives (agreement m/f -- singular/plural) & nouns/pronouns. Yikes. But, it's not really that hard. Hardest thing for non-Romance language speakers (like many of us) is the whole masculine-feminine business since English, for example, has only gender for male and female beings (well, and ships and some cars).
The concept of grammatical gender has little to do with maleness v. femaleness. It has to do with the etymology (geneaology)
