Any suggestion to improve my writing skills?

I don't know if you are asking how to improve the actual writing, as in penmanship or if you are asking how to improve them in technique, specific to something. So, I'll answer it both ways:

To improve penmanship, PRACTICE - PRACTICE - PRACTICE. Develop a certain style that is comfortable to your hand. Write slowly, take your time. Keep a journal, write letters, the more you write the better your penmanship will develop.

As for technique...take a creative writing class, copy (not plagiarize) the style of a favorite writer. Decide what you want to write about and research that topic. There a lot of books on the market that can help you in the way and what you want to write about.

try to write things and repeat

First, you have to write a lot. even if it doesn't come out good, that's the only way to improve.
Second, you have to read a lot, and focus on the stuff you like and ask yourself what makes it work in your opinion..