I put up a link to some basic care instructions for you. If you need more specific information, it would be good to say what way your plant seems to not be doing well. That way, I can consider what might be happening.

Does your tap water contain chemicals such as chlorine, floride or salts? If yes you need to use water without those additions.

Here is a link that might be useful: Basic care instructions

To check your lucky bamboo if it's health.
1. Check the stem by pressing; it must be firm.
2. Check the roots by smelling - a healthy bamboo has a fresh smell, and no black spots on the bottom tip.
3. Check the leaves to make sure they are thick and dark green.