Doing some adaptations, we could use this question to ask ourselves:
Which routines could you start/stop that would have the biggest impact on your health?
Which problem you could solve that could have the biggest impact on your life?
Which changes could you make that would have the biggest impact on your home?
As it happens very often, there are many ideas that can be generated. However, there will be some ideas that are the ones that you really believe on them. They are the ones that are more interesting and easy to be implemented for you.
As I have mentioned before, the first books I read about personal development were published by a prestigious university about business studies that used to post their publicity to me when I was less than 18 years old. There were very reputable business books that provided information for business development and at the same time for personal development. Then I adapted the information that was written for businessmen to my situation as a teenager.
For example, let´s take the topic of HEALTH. There are so many things that can be done to improve our health. However, each individual has his/her own motivations, experiences, hobbies, life styles, jobs, beliefs... that is why the question about improving health must be addressed in a very personal way by thinking about our routines, changes that we feel are easy to be implemented and sustained.
There is something interesting about the concept of HEALTH, as the immediate meaning can be attached to physical health (weight, etc.). However, there are also other implications such as "mental health". And then, we can start talking about other fields, such as spiritual health, financial health, working life balance, healthy relationships, etc.
From this point of view, it could be interesting to use the analogy of physical health to improve other types of health or reversal.