Keeping a journal is very good! Just don't let it be a record of what you have done today, but an evaluation tool. When I keep a practice journal - there are periods when I don't, due to general lack of time - I write very short reflections on what I have done, and then I immediately make plans for the next session. The next session, maybe next day, I start with checking my journal plan, sometimes I print it out as a check list and put it on the piano, and then I play and check the items I have done... and then I evaluate it again, make new plans and/or keep some items I don't feel ready with, and so on.
I use Microsoft OneNote as my journal tool because the word processing is a minimum and you can easily combine the text with images, links and everything you like. But there are plenty of tools, and even plain notebooks will do, of course ...
I can honestly say that I learn far quicker this way.
When you encounter a specific, difficult part of the piece, let's say two bars - don't be lazy, don't just struggle with it over and over and over again (slowly, very slowly, or begin from the beginning and try to pass it like a hurdle - one day I will make it!) but really try to make a pause. Don't play for a moment, just evaluate it in your head, try to figure out EXACTLY where you are going wrong. And what is going wrong. Then you CONCENTRATE your efforts on this very spot (plus one note before and one note after) for a while. Don't allow yourself to "begin from the beginning" once more! Just focus!
Here you certainly have the best use of a good teacher, but maybe you don't have access to one right now. The most common problem is that your fingers are not sure where to go next, or that they are forced to make a movement that is not comfortable. Or may it be a rythm issue, hard to synchronize the hands?
Well, in the first case I suggest that you make a thorough analysis of the harmonies, if you haven't done it before. When you have found them, you may need to invent some exercises for the chord progressions. Play the scales and the inversions.
You can also try to simplify the score for a moment. For example, play just the notes on every beat and skip what is between. Or just the first root note in every bar for the left hand while you outline the melody a bit more in the right hand.
Another good way which I like to use is chord blocks. You have your hand in one certain position, then play all the notes simultaneously in that position, then PLAN your move to the next position, THEN you do the jump or the shift quickly, play. Do it again - first chord block, second chord block, do it up to speed and even faster for a few times. Yes, it may sound horrible. So what, you are learning, not performing!
If you have uncomfortable movements and/or transitions, try to explore a better fingering. Maybe the other hand can "take over" some notes? Find a suitable fingering pattern and exercise it over all octaves. (Yes, changing the fingering is a hard thing to do, so the sooner you can identify issues like these, the better!)
Then you always have the solution of cheating ... Sometimes you need to simplify the music a bit in order to play it at all. If you have a complicated chord where you need to stretch too much and have a hard time making it to the next move, you may skip a note in it. In the old days, performers were almost expected to make their own free versions of a composition, not follow every fly sh*t spot rigorously.
For rythm, you've better count ... maybe away from the piano, maybe dancing while you do it. I had a rythm issue where my teacher suggested me to lift my hand up high between every keystroke. The delay this movement caused, was exactly what I needed to get the rythm right. (I am not, of course, supposed to make this rather ridiculous gesture later on, it is just for now, while I'm learning it.)
All these supporting exercises have the great benefit that you DO NOT just repeat the same thing over and over again, with errors and all, hence practicing mistakes and not the right thing.
Of course you must also restrict the number of repetitions, it has been said before by others here.