How to succesfully improve?

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Did you just become a diamond member?  I know you said you are a non native English speaker but your language skills seems fine, so I'm wondering why you haven't hit the Chess Mentor a little harder?  Of course you need to play and review your games, but a solid knowledge base helps too.  Most bang for the buck comes from tactics training according to many experts.   If you were to really learn all the tactical motifs, and CM has maybe 15 to 20 courses on the individual motifs,  I bet your play would be much improved. GM Patrick Wolff wrote most of the courses and while they don't have as comprehensive an explanation as some of the newer courses, they're still quite valuable.  If you learn better from videos, then IM Danny Rensch has a whole video series covering the same ground.  Good luck with your game and I hope I've encouraged you to take advantage of your diamond membership. 

I agree with the above suggestion to use Chess Mentor. I have also found that the Study Plans under the Learn drop down menu are very good and are set up in a progressive manner.

Good luck.

Play less of the 5 minute games and more longer ones 

These threads come up all the time.  You are the first player I remember who's posted that has played more than 20 games here.

ELO 1000 players know a little about chess.  Typically they know a little bit about thier openings and play trappy lines for quick kills.

They see simple tactics so it is important to not leave your self open to pins and double attacks.

Most games are decided on material advantage usually fron dropped pieces.

My advice then is. 

1, Play a lot of games. 

2.  If you haven't yet, focus on just enough openings to get you through most openings.  An opening for white with a main line and a 'universal' structure. As black a reply for e4, d4, and a 'universal' structure.  There is nothing wrong with playing bullet to flush out your openings.  You can easily play 15 games an hour and 80% of the openings you see will be the same four or five.

3.  Tactics, do at least a thousand...twice.  Any book will do.  Reinfield is accessible in any language.  chesstempo.com is a good place to study tactics.

4. Play lots.

Go to chessgames.com and play through all of the games of Greco and Morphy. Play through these games fast so as to absorb the patterns. When you play live, play the openings that you saw in these games as far as you can remember them, then be alert to tactics.

Not only will you improve faster learning ancient games, you will build a better foundation for learning more advanced skills later.