First you must determine the type of room that you want to create in your basement. This will drive your basic layout. A rec room, for example, may include a wet bar and and fireplace. An in-law suite may need a bathroom and a small kitchen. You may want extra storage in a playroom or a craft room.
Set a realistic budget. Take time to price your materials for the project and the cost of outside contractors such as electricians and plumbers. Factor in the cost of tools that you will need to buy or rent. Set the budget slightly higher than your cost estimate so that you're prepared for the unexpected.
Before a remodeling project can begin, you must ensure that it's completely dry. If necessary, have a professional inspect the basement for any moisture problems. Sealing and waterproofing the basement may well be a necessary step.
Plan for the number and location of outlets and any plumbing changes needed for the type of basement room you want to create. A bathroom and kitchen may require substantial plumbing, while a home office might need minimal changes. Unless you are especially skilled in plumbing and electrical work, plan to hire professionals for these jobs.