I have watched and read a lots of films and books.

Never 'a lot'

I usually love watching mysteries and thriller movies which have made me to realize a lot of things that i did not give muchpay attention to before.

Pay attention is more idiomatic

So from now on i plan to write my reflection , the things and what i learned and from the movie I watched or the book I read.

I hope it will help me not only to improve my writing skills but also overcome the struggle of reflecting on my thoughts.

I usually love watching mysteriesy and thriller movies which haves made me to realize a lot of things that i did not give much attention before.

If you pluralize "mystery" here, it sounds to me like you like watching "mysteries" and also like watching "thriller movies." But "mystery" should actually be adjectival here. "Mystery movies" and "thriller movies".

So from now on i plan to write my reflection (?), the thing i learned and from the movie I watched or the book I read.

You can "reflect" on things that you've watched, but I feel it's a bit of a heavy word here. It's often used in forms like "reflect on your actions", to consider your behavior and the (negative) impact it's had on others. But I also feel "reflections" isn't really used to refer to the thoughts you have while reflecting. I think just plain old "write my thoughts" is best here.

I hope it will help me to not only to improve my writing skill , but also overcome the struggle of reflection(?) my thoughts.

"reflect" being a verb and having "my thoughts" as a direct object, "reflection" is the wrong form here. Though I'm not entirely sure what it would mean. I think you might say "organize my thoughts" or something like that here.

I have watched and read a lots of films and books.

I usually love watching mysteries and thriller movies, which have made me to realize a lot of things that iI did not give much attention to before.

So from now on iI plan to write my reflection on these, the thing is that I learned and from the movies I watched or the books I read.

I hope it will help me not only to improve my writing skill but also overcome the struggle of reflectiong my thoughts.