Drink and eat regularly during the ride to avoid dehydration and the 'bonk'. Carry extra food and water.
Don't rely on minimum lighting requirements. Consider carrying a second front light or a dynamo system in addition to a main front light. It is strongly recommended that riders use more that one rear red light. Wear a reflective vest, reflective leg bands, and other brightly reflective clothing.
Carry a tool kit, spare inner tubes (and patches), and perhaps a spare fold-up tire. Be sure your pump is working.
Be prepared for BC weather. Make sure you take along clothes to protect you from cold and wet conditions. Fenders with mudflaps are strong recommended.
Ziploc bags are useful for keeping control cards, route sheets, and computers dry.
Road surfaces vary. Narrow tires suffer more impact punctures but wider tires have more drag. If riding a mountain bike, consider using slick tires.
Use a sensible gear range. Late in a brevet those hills can be daunting if you don't have the right low gears.
A broad map of the area can be helpful if you stray off course.
More recommendations in articles on the randonneur toolbox page.
Personal Liability Insurance
To protect yourself, and your riding companions, it is strongly recommended that every rider have personal liability insurance. Many will already have this sort of insurance as part of a tenants or homeowner's insurance package. Alternatively, Cycling BC may be helpful on this matter - many randonneurs are 'insured members' of Cycling BC. The cost of an insured membership in recent years has been $50+, and includes other cycling related benefits. You can contact Cycling BC at (604) 737-3034, through the web site www.cycling.bc.ca , or by e-mail firstname.lastname@example.org