You should read this, it is helpful: http://french.about.com/od/grammar/a/adjectives_4.htm
Here's a little rhyme to help you remember which go in front:
Mauvais, méchant, vilain, beau,/ Petit, haut vieux, joli, gros,/ Nouveau, gentil, jeune et bon,/ Grand et meilleur, vaste et long,
[it doesn't fit in anywhere :)]
Also, dernier and premier go in front (as far as I know), and propre means "own" if it goes in front (ma propre chambre = my own bedroom), and tidy or something if it comes after the noun...
(Sorry, I've had to put / in because it won't let me put them on different lines.)
"la femme" (singular) cannot be women (plural).
"la femme" can be "the woman" if she is specified: la femme est assise sur un banc = the woman is sitting on a bench
"les femmes" can be "women" depending on the French meaning:
- men are stronger than women = les hommes sont plus forts que les femmes. that is a generality (universal truth about men/women in general), to be constructed with definite article le/la/les in French.
"women" can be "des femmes" (plural of "une femme") when it just mean "more than one woman"
- des femmes ont reçu des fleurs = (some) women have received (some) flowers