a Particle
Method or means
Using what, or how
日本語で話してください。 Please speak using Japanese
Material
When expressing what material something is made from, で is used if the thing clearly looks like it's made from that material. Out of (...) is more suitable when you cannot visually judge what materials are used to make products.
~~竹から~~弁当箱を作ります。 竹で弁当箱を作ります。 Making a bento box using/from bamboo.
家を木で建てる Build a house out of/using wood.
State
ふたりで遊ぶ Playing together (with two people)
洋服で東京に行く Going to Tokyo in the state of using western clothing
Causation
similar to から, but not as strong. Also ties into and (...).
電車が雪で止まる Because of snow, the trains stop