Goal setting is the art of getting what you want out of life. You write down your objective then sit back and watch events unfold. At some point you will feel the urge to take action - so get up and do what needs to be done.
Goal setting should be a priority on your training schedule. There's no point aimlessly drifting from one night at the dojo to the next. That's how hobbyists work. They "go to karate", they don't study the martial arts. There's a difference.
Setting a goal puts you in charge of your own training. Your lack of progress can easily be blamed on everyone or everything else (sensei doesn't pay attention, too busy looking after the kids, no room to train at home...)
The reality is that the only person responsible for your progress is you. When your instructor tells you it might be a good idea practice such-and-such a kata there's a subtle hint there about what you could do to improve your progress.
So write it down. "This month I will train in Niseishi for 10 minutes per day". Read your goal twice each day - once in the morning and again at bed time. When you get the urge to train, just do it. Don't set a specific time each day, just allow it in when it happens.
There's a little discipline involved, but no great hassle. Hey, this is martial art! It's a DISCIPLINE. Forget about fighting for a while - the whole purpose of martial art training is to find peace of mind through discipline!
You can even train without getting out of your chair. It's called creative imagination.
Sit quietly for 10 minutes, relax your body and calm your mind. Now surely *that* can't be difficult can it?!
When you're ready to begin watch yourself in your mind's eye performing the kata. Not any old kata, but a textbook kata. It's as good as perfect as you can get. Put all your emotional intensity and feeling into the visualisation.
Then do the same visualisation, but move the camera angle. Watch yourself from a different angle. Then do the routine again, but this time enter into your imaginary body so now you are doing the kata as you would experience it in the solid world. You might even feel your muscles twitching in response to the visualisation. That's because your mind doesn't know the difference between imagination and reality and your muscles are simply reacting to the feeling of the imaginary kata.
(There's an interesting aside there: the quality of your training/life depends entirely on the quality of your thoughts. Guard them well!)