In English, as you know, the adjectives always come before the noun and, when there are more than one, this is the most common order:

When the adjectives are of a different category, we DO NOT use a comma:

- A new steel steak knife.

- That big red plastic bag.

When the adjectives are of the same category, we DO use a comma:

- A distinguished, friendly, beautiful woman.

- Two beautiful, soft, comfortable cushions.

If you can join the adjectives with AND or BUT, then use comma. If not, do not use it.

ACTIVITIES:

http://learnenglish.britishcouncil.org/en/english-grammar/adjectives/order-adjectives

http://www.learn4good.com/languages/evrd_grammar/adjective_order.htm

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/adjord2.htm

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-42493.php

http://www.learnenglishfeelgood.com/esl_adjectiveorder4.html