A piece of advice I heard on a YouTube channel was commit to just 5 minutes practice a day, even if you just pick up the guitar and noodle. Setting expectations you can't meet can be very disheartening so planning to practice an hour a day when you haven't got time is really self defeating. If you've said to yourself '5 minutes', you can fit it in and once you've done it you can feel good about it, but I find that the five minutes is more likely to become ten, of twenty or more. Obviously structured practice is best when you have the time but even short regular sessions is better than going in hard one day then not touching the guitar for two weeks!

The other thing that's worked for me personally is that Rocksmith keeps track of your consecutive days of practice and since I'm now in the something thousand days, that's a lot of motivation not to let it drop. I've practiced through severe illness, remotely while on holiday and when we had to leave our home for a month.