If your basement is damp or wet, this has to be fixed before any finishing work can be started. Most water issues can be fixed by grading the soil to slope away from the foundation and repairing gutters and downspouts. If these preventative measures don't help, more excessive action will need to be taken. Stopping water can be time consuming and expensive, but if it is not fixed you will end up with a ruined and moldy basement.
Insulating exterior walls prevents condensation. It also saves energy and reduces your energy bill in the winter months.
Use as much natural light as possible to brighten up your basement. Often, it is assumed that basements have no natural light to give, but often times that is not true. Take a look around and see where you can take advantage of natural light for your basement.
You will most likely need to add vents and a return air duct to your basement when you are completing the remodel. You will also want to have a carbon monoxide detector installed to monitor the air quality in the basement.