This is very good question, regardless the weakness in your company. giving you no training plan that steps together with your career path.
You said "I failed with the task that I've been assigned to me" .. this statement stopped me ... how a designer fails in an assigned task?
does your design are bad? or you just spent so many time doing your job? where exactly your fail is?? your statement is a fussy one. you should ask your company about your exact fail.
Anyway ... the important question is "how to sharpen your talent?" this is not an easy question to answer but I will try.
Actually there is no way to sharp your talent but to work and work and do more work. train your "third eye" the eye of the wisdom.
In the beginning of the renaissance age. "Philibert de L'Orme" a French Architect has drawn two illustration hereunder showing a "bad architect" and a "good architect" .. I will explain that based on my background and as an approach to answer your question.
The "Bad Architect" illustration shows a blind homeless man with no hands lost in a Goth land and the style of the buildings in the background are Gothic. The Style which was representing the dark ages and ignorance.
The "Good Architect" illustrations show a wise man that walk in a paradise with classical style land having four hands and a third eye Above his forehead and give advises to a young man most probably a disciple.
What "de L'Orme" whated is a revolution over the old Gothic architectural style with a symbolic and philosophic way.
The Good Architect have 4 hands that's mean he works so hard, having a third eye mean he is enlightened -the third eye by the way exist in the old Indiana culture representing the enlightenment eye of Buddha.
Anyway What I want to say, you must work hard as if you have 4 hands and train your mind for observation. be a good observer. and once you did you will look into the same things of ordinary people see but in a different way. and be sure that everything you do, there is so many ways to do faster and better. design is an endless process.
you should do the 3L's (Look, Listen and learn)
