I want to start writing my own programming. Do you have some general advice to help get me started?
Here are some 'signposts' that will help guide your training in a more meaningful fashion and help you start to frame out your own program:
1) Goal Setting: Training schedule will depend on your goals. If your goal is to be better at your job your program will look a certain way. If your program is to be a better triathlete and be better at your job then your program will be different. There is no such thing as a "one size fits all type" of program. Define all of your goals and start from there.
2) Training: We generally advise that at most a person can truly go hard only 3 days a week. By hard I mean really truly hard at maximum intensity. People think they can go hard 5x days a week but perceived exertion is not a good measure of intensity. You may train more than three times a week but the other workouts should be comprised of recovery workouts. A schedule could possibly look like this:
Monday: Hard Gym
Wednesday: Hard Gym
Friday: Hard Gym
As for additional work you can always add things to the schedule. If you add to the schedule though be careful to monitor your recovery status. Add low impact movements like rowing or biking. You could also add more running or hiking with load carriage depending on how destructive running and hiking are on your body. Some people are good on their feet and resilient to volume injuries. Some are not. If you would like to add endurance work to the mix you may do it on the recovery days depending on how destructive the work actually is. For example 90 minutes of easy paced cycling may not be destructive but a 90 minute road race may be. If you want to do two a days that will be acceptable some days as well. If you do this do the endurance work afterward (later on in the day) after you have done the strength type work in the gym. It will make the endurance work more efficient and will not compromise your strength type work.
3) Recovery: Do not underestimate the value of recovery. It is arguably the most important and often ignored aspect of training. Plan your workouts accordingly. Engage in recovery practices on a daily basis including recovery showers, foam roller sessions and recovery walks. Remember that "Training = Work + Rest". You should put as much effort into recovery as you do into your training.
4) Diet: sort it out now. Diet is as individual a concept as training is. Eating to gain mass is different to lose mass. Eating for high end performance is a completely different animal altogether. Pay attention, find what works for you, and be disciplined.
5) Read: There is a lot of knowledge housed within this website. Read all of the articles on the site and take time to go through the schedule. It goes back quite a ways. It will take awhile but the investment is worth it and will answer many of the questions you have.