In GoldWave, press F11 and choose the Device (or Volume) tab. Adjust the volume as needed.
If volume cannot be set to a suitable level, make sure that any external volume controls are adjusted as well.
If volume always clips at about 50%, contact the manufacturer of the sound card for advice (usually the driver or hardware is defective).
If you are using a microphone, make sure it is connected to the microphone socket and not the line-in socket.
If you are using a microphone, use the Windows Volume Control accessory, set it in Record Control mode,
then use the Options | Advanced command to display any advanced options.
If the Microphone control has an Advanced button, choose that and
look for a "microphone boost" setting or type (dynamic or condenser) setting.