There are many different components in your car that can cause abnormal noises. The best thing that you can do is to identify when and where you hear the noises. Is the noise when the car is going fast or slow? Hot or cold? Front or rear? Left or right? is it all of the time or intermittently? If the noise is intermittent try to identify what conditions are present when the noise is there. All of these items will help your mechanic to identify the problematic area.