Calculation improvement.

Hi all. I'm stuck with it. It's very very difficult to see forks or other quiet moves after loud ones. I'm doing tactics training almost every day and i don't think i have a patterns recognition problem. Looks like my mind is limited and it's very hard to make futher progress. Is it possible to get over such limitation? What training plan could you suggest for me? Thanks in advance.

How long have you been practicing?  What is your "end" goal in order for you to think you have really improved with your tactics?

The truth is you can't rush chess improvement unless you are truly gifted. It takes time, practice and patience.

More importantly, how have you been practicing?  Deliberately or just some time-driven 30-mins a day routine? 

Can you walk us through a single tactics training session?

For example:

1. I take a puzzle position. (Is it new or an old one you encountered before?)

2. I spend X minutes on it.

3. I check the answer.

4. If I get it wrong, I do _______?

5. I try to see why I got it wrong; what pattern am I missing?

The practice quality and habits might be completely wrong for your "brain's" unique way of learning + acquiring skills.  

For example,  the "go over tactics in a puzzle book endlessly" did nothing for my improvement. So I switched gears and started repeatedly doing the same "basic" tactics puzzles (Bain, CT ART etc.) over and over again and trying to see if I could "see" the pattern jump out of the position in less than 1 second.  If I took longer, I would count that as a failure.

Once I started accumulating 500+ patterns with this method; then I started to work on more calculation-oriented challenges with analytical positions (not necessarily tactics puzzles) that were new and I would write down all the forcing lines and my evaluation of them.  Then cross check these with a computer.  NM Dan Heisman advocates doing this and a whole lot more in his Stoyko exercise practice.

You want to spend a minimum of 20+ minutes on a single position looking at every forcing line you could ever calculate. There are several books that offer positions like this ... this is way better than your typical "only one way to win" tactical shot puzzle.

I've done this from time to time and always felt my calculation +  visualization skills got better :)

I've been practicing for about 4 or 5 months since i've bought that premium membership. You can see how many puzzles i've done - 2000. What's the difference between practicing deliberately and time-driven 30-mins a day?  I do it deliberately but not very long. Maybe one hour maximum. Also i'm trying to increase my tactics rating which is hard because of time. I can have no more than 1800 rating. I can solve puzzles with rating more then 1800 but time holds me back. If i get a puzzle wrong then i do it again and second time usually is enough. Thank you for Stoyko exercise. It's very interesting.

GM Jacob Aagaard has a book mainly on calculation. It's from the Grandmaster Preparation series. They're main focus is to train the reader that doesn't have a private coach. They're really interesting and the positions themselves are intriguing. I actually own the series, although I haven't finished them. They require a lot of time, which I don't have. Anyways, it's just a thought. 

What do you think is better to solve many simple puzzles or one but very hard? I solved a hard one today. It has many deep lines and it was challenging for me. I feel tired when i solve such puzzles. Energy consuming to keep many variations in the mind and also it takes much time.

That is not that simple to answer. It is recommended to find hard exercises that you are able to solve because it will do you no good trying to solve a puzzle that is too complicated to understand. You need to gradually increase the difficulty of the puzzles as so you get more and more familiar with the motifs of the positions. That way you will waste less time calculating because your intuition will get better. And if you think you aren't making any progress, it's not true. You will get better, even if it doesn't look like it. It's like if you move to South Korea for a year. After the year has passed I can assure you that you will have learned at least a little Korean. Same with chess, if you study similar positions, after a while you will instantly see the patterns and resemblance. But answering your question, you shouldn't try to solve extremely difficult positions, let alone compositions (excluding endgame studies) where there is really not a theme. And you should try to solve it without giving up instantly. My recommendation is to take up to 20 minutes on the puzzle or exercise, ohh and don't touch the pieces, try to solve it in your head. Just my opinion.