Hello, I don't think there is a failproof way to tell if a noun is masculine or feminine, but if you know how the word is written you can look at the ending. Most feminine words end with "e", but there are always exceptions. I know there is this video: https://www.francaisavecpierre.com/le-genre-en-francais-masculin-feminin/ I have not watched it so i don't know if it's any good. I recommend reading anything in French and look at the determiners to see if it's masculine or feminine. Good luck !