Poker How to win more when Showdown

Firstly, i'm very happy when join a Poker community with too much knowledge like this.
I'm new to poker world, and have started to play Pokerstars for a month. So, there was too much mistakes i've done in about 400 hands recently.

Actually i know all about Poker rules, but it seems like i'm too optimistic about my hand, or i dont believe about villain' hands.

And as you guys can see, my blue line is almost negative all of the time.
Maybe it's too little hands to see anything, but can you guys tell me how i can improve my play in the long run.
I wanna learn poker seriously.

Thankyou very much. (Sorry for my bad english).

this is my report for 400 hands: https://imgur.com/a/dOAttvz

Source.