The Master Skill

It is the time of the year to call for more training and skills upgrading. We need to raise our skills, go for more training to improve productivity, and then to increase our income. I fall nicely into the group of 45 to 65 that needs more training and better skills. I need them, for I have another 20 or 30 years to go. Like I said earlier, enough time to start another family or to build a new career. The future suddenly brightens up. So much to look forward to. In the past I was only looking for whatever little money left in the CPF. Now got chance to start a new career, go for job interviews and asking the organisation about promotional prospects. Feeling like a new person again. Got to search for my certificates and testimonials and dust away the dusts, and make photocopies of them. Now, how to write an application letter? Forgotten how, too long ago. Training first. Come to think of it, if I could have gone for the right training and learn a master skill, then there is no need to go for more training at this young age of 60. Is there such a master skill that one can acquire and become a knows all for good? There must be one that allows one to be so skilled that one can switch industries and jobs like changing clothes and still continue to enjoy high pay, high perks and high bonuses year after year, unending. And the best part, no more training needed. And one's value and talent and skill get better everyday. Can anyone advise me on where to learn this master skill? Or is there such a master skill?