Job application (2/2)

Another of my strengths is my organizational skills. I have a good sense of how people and resources need to be organized in order to meet goals. Actually, when I was a student, I used to be a high-level athlete. I followed my engineering classes while I was training 10 times a week. (Or you may say: " I managed to succeed in my engineering classes while I was training 10 times a week." Such way you could better emphasize your skill.)

Hi, Robin! Hope my correction and suggested use of vocab can help you.

One of my greatest strengths is that I am very proactive. Due to my serious way of working, I don't hesitate to take initiative when it is necessary. English is not one of my natural strengths, but I'm now working it hard to become operational in English. I feel that it is something I will can do well. 

You can use either 'will' or 'can' in the bit I highlighted in red, but you shouldn't use both.

Also you should definitely remove the 'it' from "working it hard". "Working it hard" has sexual implications. :P

Aside from that, mostly fine!