struggling to convert advantage into victory

hello all, as you can say in the match that I linked here (https://www.chess.com/analysis/game/live/87237552557?tab=review&move=53) I've some issues converting advantages into winning games. Obviously, i made some mistakes in my evaluations but i can't really understand why i completely miss opportunities in those situations. If you can give me some hints about what's should be the problem(s) and how to try to solved it, it will be great.

p.s. Of course, i made lots of puzzles but it's like I'm not able to convert my ability to solved it into some game improvements at the moment

In game, I completely missed the Qxf4, I saw it immediately during my review, so there is something wrong with what I paid attention during the game

Hi! I didn't look with the engine so I may be off with some of what I say.

First off regarding the opening; Bc4 vs the Sicilian is a way to play, but it's quite off beat. But indeed 4.d3 is showcases a problem which is bigger: you are playing automatic moves in a slow game. In other words, in a game where you have time to think "how can I punish my opponent's h6??" which is clearly a bad move, you chose not to think but to play an automatic move that you learnt from some other opening which has absolutely no relationship with the current position what so ever. So rather than focusing on this move I would focus on the issue it conveys which is... if you are on your own - think for yourself. If you are "in book", play what you learnt.. Mixing the two is not great most of the time. And if you take your time, think for yourself, make a mistake and end up in time trouble - that's fine! In the long run your chess will improve more. And also I think you will be surprised how well you do.

So playing "Italian", or any one setup or system vs everything is not just a thing. You are clearly better than that!

And by this I mean - you clearly have an eye for tactics. You did have a nice sequence and you were doing fine, but don't always take Stockfish's evaluation so seriously. He may say you are crushing because he sees all the way forward whilst holding everything together... But for a human - any advantage you have where you prior lost a center pawn for nothing, and got isolated doubled f pawns - is a very shaky advantage... And by shaky I mean your opponent will always have counter play - the game may be considered a "crazy game". There is no way your advantage is ever solidified with doubled f pawns, an isolated center pawn, and queens on the board. The engine can scream +10 and it's just nonsense. You have a shaky position, and it demands attention and accurate play not conversion. An advantage is convertable only after there has been some simplification and solidification of the advantage, or you are mating / forcing opponent to give more material.

I agree with everything @AlekhinesRazor wrote but I don't think move per move analysis will help you understand.. I would however like to focus on one type of move that recurs alot. "One move threats", aka "shooting from the hip"... If you want to improve your game you should only go for one move threats if you have a follow up that improves your position still, or preferably play deep ideas that have double or triple threats with ready replies to all of opponents responses including his best responses that you can see. I do believe you could have seen many of your opponents "counter punches" if you had only looked for them... Ultimately it was yet another one move threat that forced your opponent to make the completely unnatural move g5... Ok maybe g5 is a great move even if you don't play the one move threat "Bh4?", but a 900 would have never played g5 if you didn't force him to see that he's trapping your bishop in two moves. So his g5 did indeed have a follow up.

Hope this helps.

So if I have to sum it up to concrete tips:

1. Learn some opening ideas.. not to delve deep in to theory just to have a feel for getting solid positions that you actually understand. You don't want all your games to be crazy games where you get islotaed doubled f pawns, lose a center pawn, and your opponent just makes more mistakes than you and you somehow win. Chess is also about control and being solid, and deep understanding of positions; not a lottery of tactics.

2. Don't play one move threats that don't improve your position. Look for opponent's best replies to determine the outcome of moves, and make definite evaluations of the arising positions you see in your mind (being wrong is fine... being ambiguous is not)

3. Don't consider any advantage you have as stable when you are in a crazy game. Keep playing your best until checkmate, don't think it's a matter of "conversion" unless it's a simplified and clearly winning endgame.

To me it just looked like a crazy game, and I honestly saw no solid advantage for White, but again, I didn't use engine.

All the best and good luck !

Thank you for your suggestions, they are really helpful! 
From your comments, I think the part where I struggle more is to understand the board position and how can I improve it in a solid way, so if you know books, courses, videos, or exercises to suggest, it will be great.

it's not a matter of which but how? when you study chess study it well!

for example study tactics, don't solve puzzles. the difference: solving puzzles is just doing online puzzles getting a green V for each move and feeling smart. -bad quality of study.

better to do puzzles from a picture that cant move writing down the solution on a piece of paper to actually calculate all the solution in your mind. If you do it online it can be the same just don't solve the puzzle, write down your solution(s) then solve, then continue to study the tactic after you solve with the analysis board to fully understand all the details and why the end result is so winning.

^^this should get you to 1300 pretty fast...

I didn't read any book all the way through but books I did some work are "Simple Chess", "Mastering Endgame Strategy", and "My System". out of all these "My System" is my favorite. also "My Great Predecessors" but that one was too hard for me.

videos: anything that's educational... Ben Finegold long lectures I do like.. Chessnetwork.. videos on capablanca.. There's a cuban NM on youtube that has nice Capa videos.

I like the Gata Kamsky videos on this website and also Lenier Dominguez videos because these guys are really inspiring to me..

Hi! It is difficult to give advice without knowing you nor your games, but I think most probably you don´t apply the CCT rule. I wrote a post on the subject, if interested check it out: https://www.chess.com/blog/maafernan/instructive-games-ii-prevent-blunders-and-profit-from-your-opponents

Good luck!

I find that some middlegame's are simpler to understand and easier to convert. Those include the ruy lopez middle game, The french middle game, And the english middle game.

Once i switched openings, Its like i unbound my chains and started blundering less and less.
Maybe this is the case with you?

You must analyze only your big blunders and forget about small mistakes!! Watching every blunder pattern of yours for ten minutes can help a lot!

the question is identifying this moment.

I find often it's not the moment the evaluation swings. Like sometimes you lose a center pawn, eval stays the same because "it's still fine", but for a human actually losing the pawn with the eval staying the same is the significant blunder... Or grabbing a pawn when you should have developed a piece, eval stays the same, but in reality you allowed counterplay...

I mean the "big blunders" as you say are not always identified by evaluation swings of Stockfish. IMO...

Bxd4 is not suicidal, pawn cannot take bishop because that pawn is pinned to the queen, this is a great move that offset black's advantage

yeah actually I did like Bxd4 when I looked without the engine and engine confirms its good

the problem is losing center pawns and having doubled f pawns in the 1st place...

for example look at this random game I studied cuz it had a nice puzzle in it

White played a "solid opening"... Alapin is considered less ambitous I think... But does that mean White played boring? No, he played crazy, very interesting... But he was in complete control most of the opening and early middle game, his center remains strong, kingside remains extremely solid which enables him to go for a dubious attack and make it work... just stating cuz I can gather OP likes tactics but can try to build his tactical play upon more solid foundations to make it work...

A long ago chess master observed that the hardest thing to do in chess is to win a won game. So you're not alone.

I've struggled with the same problem in OTB chess. At lower ratings, just putting pressure on my opponent until he blundered was enough. As I started playing masters, experts, and Class A players, that no longer worked.

The answer that finally came to me was to make a plan. It's an axiom of chess that you should play with a plan, and that doesn't change just because you have a big advantage. The nature of your plan will be different depending on what your advantage consists of. If you have a material advantage, exchange pieces to reach a winning endgame. If your opponent's K is weakly defended, bring more pieces into the attack. If you have put all the pressure you can on a weak spot and the other side has it defended, create another weakness in his position. Etc.

None of this is simple and easy, because chess isn't. And I'm not familiar with any books or videos that specifically deal with this issue. I picked up bits and pieces from annotated games until finally beginning to understand it, and I still have a lot to learn. Opponents always seem to have resources that make the job difficult. My only suggestion is to keep studying chess in general, paying particular attention to how strong players convert winning positions.

Best of luck to you.

Guys, thank you all for your suggestions, i really appreciate that!