Any tips for a slow beginner?

All very nice advice.

My only suggestion is practice visualization of positions (not even calculation). You can do it in many ways, but one of my favorites is... going through a game, noticing when you didn't have any idea what to do and then set up that position in a board and then think of ALL the legal , non immediately losing moves and visualize them on the board... visualize the new position and then reset the board and do it again. Then, either through an engine line, your own thinking effort or the help of more advanced player, choose a worthy plan/line and play it over and then reset the board and play the line through visualization. Then repeat and repeat and repeat.

Yea, play just one game a day. And read a chess book for beginners (or watch youtube videos) on strategy to learn how to make plans.

hello, I am also a beginner in chess any advise from old members? Cheers :)

That's is so stupid. He should be playing e4. E4 is what helps beginners improve. He probably doesn't know what the Catalan is and his opponent probably won't even go for it. Don't be so pretentious with your openings. 

I agree with what @redgreenorangeyellow said, recommending the catalan for a 900 is outrageous

Beginner chess books are bs because, as you said, you can get all the information on youtube quite easily. And no, he should be playing more than one game; he should be doing as many as he feels fit for the day (meaning that he shouldn't begin another game right after raging about a loss). A beginner needs to gain a sense of the game in general. 

I disagree with the widespread advice that beginners should play 1.e4. As a beginner, 1.e4 has not helped me improve at all. Some players (like me) do not play it, because it's full of traps.

Catalan like setups are not unusual, regardless of whether the beginner can play the opening correctly. They are also quite solid. Other than that... since this isn't a thread about openings, i'll shut up now.

But he can't reach the catalan or play it without learning deep theory

I mean winning 2000 blitz games hasn't really helped you improve either. 

The fact that many of those games were with 1.e4 escapes you, doesn't it?

You still should be improving. 2000 games is plenty. Don't make excuses. You are just telling yourself that e4 is the reason why you are not improving because you don't want to feel bad about yourself. 

Playing Hyper-modern openings does NOT help a beginner improve

The reason I don't improve, and maybe the OP can derive something from not doing what I do is to play only blitz like it was bullet and not play to their strengths. IIRC, the OP says it's mostly about losing focus as the middlegame unfolds. I don't think his "problems" are related to 1.e4 (save for typical pawn structures).

Most of the advice in this thread has been very interesting and hasn't involved opening choice critique. It was mainly YOU who brought that in.

It may or it may not. I don't think openings define you, but a beginner may feel far more comfortable playing hypermodern setups than classical ones. In any case, the thing for most beginners (myself included) is that the opening is mostly about getting yourself to the middlegame without obvious mate threats against you and without losing pieces. If the OP or any other beginner feels at ease with 1.e4, that's commendable. If they don't, they can try something else.

This might come as a surprise, but there are still people who enjoy reading books.

In addition, the poster wrote that he/she cannot concentrate for a long time, so it makes sense not play game after game...

I never said people don't like reading, but unless you are 1400 or above, chess reading is completely unnecessary and won't do a thing. Also if he can't focus, why would you recommend for him to read. 

a) Is this even an argument? How about: "I never said people don't like watching chess videos, but unless you are rated 1746 watching chess videos is completely unnecessary and won't do a thing."

b) What does this have to do with anything? The poster finds it hard to focus while playing a chess game, which is normal if you haven't internalized the way pieces move... Like using a foreign language for hours is exhausting. I don't think he/she has difficulties reading. Also,  don't you think that you have to focus too when watching videos? At least if you want to learn something?

I hate to be the black sheep in the family but I found books a great help in getting to 1400.

The reason it is unnecessary is because beginner chess books present the same information as what would be in a youtube video. 

I thought you meant he had trouble focusing in general, not on a chess game. Watching a video is generally easier than reading, in my opinion. If he gets exhausted playing, he should play more to train his brain to focus, or he could simply take half an hour breaks in between games. 

Think this way, did it make you improve? By how much? Did openings that follow main principles make ME improve? By how much? And in how much time?