Great question! It is really hard to workout on your own- which is why group classes at gyms or CrossFits are so much more fun because you can be with other people. But I did have to workout a lot on my own when I was in college and home for breaks. And this is an important thing to focus on. The way you train when no on is looking is most important...
I think the most important thing to do is set yourself up for success. Here are a few ideas to do this:
1. Pick and commit to a certain time each day to train. First thing in the morning is usually the best bet, especially if you have to set your alarm. This way family plans will not conflict with the training and if you are in a hot location, it will be the coolest. You will always "have time" to work out and you will be sure to get it in every day.
2. Lay out your training plan with all the details of each workout including rest time. Make sure you know the workout and keep your training journal handy to write down all your results. This will help to keep you accountable. Once you have decided what you are committing to, do it. If you are going to take a day off, then take it off and don't spend mental energy wondering if you should be working out. Either do or don't, but don't waste the energy "thinking" about working out.
3. Write down your goals for the training period. Do you want to workout 6 days a week? Do you want to complete every workout? Do you want to do some sort of fitness test at the end of the training period? Do you want to log a certain number of meters or minutes? Post these goals where you will see them - on the refrigerator, next to the bed etc. and be sure to pick a few that are process oriented (eg. do core workout every other day) and some that are performance based (eg. increase back squat by 10lbs).
4. Post motivational material- quotes, the names of teams that you will be racing - whatever will get you going. I had a poster that read "What can I do TODAY so that I am standing on the medal dock of the ____ Sprints on ____, 2016." Fill it in and post this on your bathroom mirror. You need to remember why you are doing this.
5. Be sure that all your family and friends around you know what you are trying to do. Get them on board and make sure that they do not try to inadvertently sabotage your plan.
6. Just do it. Seriously, just do it.