Most people use a red biro or a waterproof fine-point fibretip pen. A compass is not required for the easy courses, but bring one if you have one. You could trip in the woods and injure yourself, so a whistle is advised, as a safety measure to attract attention. If it is raining, you will need protection for your map and control card. An A4 size clear plastic bag will do.
Safety pins are also useful.
After registering, get changed and then check that you have everything you need. If electronic punching is not being used you can write the control codes and descriptions onto the appropriate squares of the control card, if you wish, to make them easier to check as you find each control. Most people use safety pins to attach the control card to the front of their shirt or to their sleeve. Make your way to the start Get there in good time. When your start time is called, hand over the stub from your control card if they're being used.