Humans are prone to exhortation, not just of others but also to themselves. “Don’t be nervous!”, “Don’t blush!”, “Be more disciplined!”. Who do we think we are talking to at these times and why do we believe that person is listening any more than a teenager is listening when you espouse the virtues of maintaining a tidy room?
Exhortation is generally ineffective. Understanding can be very effective. Are you telling your brain how to learn a language or are you seeking to understand the language learning mechanism in your mind?
Why does your brain concentrate and why does it stop? How long is it happy to concentrate for? Under what circumstances? What role does emotion play in fatigue? What is the best time of day for you to learn. Etc. Don’t listen to the experts – pay attention to your mind.
Here is a useful exercise if you are struggling to maintain your language programme in a disciplined way. Imagine (really imagine) that you are talking to you but the you that you are talking to is only 9 years old. How would you help that child to maintain their language programme? Wouldn’t you find a better alternative than “just do it!” Wouldn’t you naturally take emotion more highly into account than you do with yourself as an adult?
I encourage you to notice your own behaviour and any time that you hear yourself exhorting yourself to do something stop, laugh at your own madness, then replace that exhortation with a question. Seek first to understand, then to be understood.