Start from the basics, even if it's just writing letters over and over. Make sure you are holding your pen/pencil properly and practice, practice, practice. I would suggest working on print first if you just generally want to improve. Cursive letters work differently in the way they are written, so don't worry about that for now.
Originally Posted by LauraMix
P.S: What I do not understand is that, How am I good in PC games but terrible at writing?
These aren't really related? But besides that, I would assume that you like to play games, so you do it often. You end up getting practice. Writing is something different, just need to practice that too. Everyone starts with chicken scratch writing.