Unless you're a pro mountain biker, it is likely that you are fitting your riding/training around obligations like study, work and family time. If this sounds like you, developing a structured riding routine could be the first step towards greatly improving your mountain bike fitness and ability. A "routine" can often be easier to manage than a "programme" in that it is very flexible and easily tailored to your lifestyle, aside from the fact that it will get you to a new level of fitness.
Whether you want to organise your week to get in more rides or you want to improve your XC lap times, you should start putting together your routine today. Using a some paper or even a calender (computer calenders work well) mark out all of your obligations and time constraints, leaving blank all of your spare time. Once this has been achieved, you can slot in the times that are convenient to ride or train. If you don't train and only ride trails, lock in a dedicated time slot for some/all days of the week where you want to ride and stick to it. For your routine to work, your 5:00pm (hypothetically speaking) evening ride should be as important a deadline as getting to work at 9:00am in the morning. Getting some trail buddies involved as well will increase enjoyment and keep you motivated and riding throughout the week.
Include a rest day or two to allow you to rebuild and recover. It is also a good idea that you include a week of recovery also about every 4 weeks. This can include gentle spinning, walking or even time off the bike if you wish
For the dedicated racers out there who aren't up for the rigidity of a strict program, plan your week with a certain training session each day. For example:
Sunday - single track ride
Monday - rest
Tuesday - indoor trainer intervals
Wednesday - long, steady distance ride
Thursday - Gym session, skills session
Friday - on the bike, long intervals
Saturday - long, steady distance ride
You may wish to consult with a coach, experienced racer or some book/web resources to get some good cycling workouts into your routine. Remember when putting together a routine, avoid having consecutive days with high intensity workouts to prevent "burnout". Alternate between high, and moderate to low intensity days with a rest day thrown in there somewhere.
If you are following the cycling fitness basics, you can easily tailor your training to the different stages of your season. For example, in the base phase, you may wish to increase duration on your endurance rides by 5 minutes each week; ultimately, follow the overload principle to keep improving your fitness. - If you are following the overload principle, it is important that you have a week of recovery every 3-4 weeks which includes backing the training load off a bit to allow your body to rebuild. Some recovery rides in your recovery heart zone are beneficial.
You should now have the tools to construct a tailored riding routine to fit into your week. Remember "If you don't have time, MAKE TIME!!"