1. MOST BENEFICIAL: Switch tires to a semi-slick tread pattern (less pronounced knobs), depending on your experience and the difficulty and slickness of the trails you will be on. Wider tires don’t slow you down, but heavy, knobby tires will. Ask your local bike shop what they recommend.
2. Inflate tires to a higher tire pressure (at the cost of some comfort so not recommended for longer races where you want to take care of your body).
3. Lock out your front shock if you have that feature.
4. Get clip in pedals and shoes which help you pull as you pedal and stay “locked in” to your bike. Once you learn, it feels perfectly normal and safe. Just start with your pedals in the loosest position and practice clipping out on grass.
5. Set up a bike tow system if one of you needs some help at times. This can be a HUGE time-saver if one of you bonks. It also can be dangerous to be tied together. Requires practice and caution, including “un-tying” on the fly which can result in the leash getting caught in the spokes of the “lead dog” so un-tie when stopped or close to the lead bike.