I can only reinforce and expand on some very valuable advice already given by others. I find that setting aside enough time to practise is difficult with work committments (I am a full time music teacher who only occasionally gives piano recitals these days), but I do make the time. Trying to maximise the efficiency of practice is crucial as well. For example, not wasting time just playing the same difficult passage over and over, tripping up at same places, physically or mentally or both; rather, drilling down to the problem, identifying it, then working hard to fix it through very focussed and intensive practice. This sometimes involves adjusting the fingerings as well as slow practice, gradually building up to the required speed and then placing back into the whole context of the passage or movement. This approach is nothing new of course, but I am very rigid with it given the limited time I can find to practise properly.
Correct fingerings are absolutely crucial, but not crucially absolute. At the end of the day you should try out alternatives and eventually settle on the finger choices which feel most natural and comfortable for you. However, once you have settled on your chosen fingerings then stick to them in a subsequent practice. Constantly changing fingerings will only add even more confusion in the long run.
I absolutely agree with the idea of studying away from the piano with the score, imagining your way through a piece. This also helps when memorising. A teacher once said to me when I was a piano major myself, you do not know a melodic passage until you can play every note with one finger. I thought at the time he was being rather pedantic, until I heard him play a recital in which he was virtually note perfect, with excellent attention to detail too in terms of dynamics and phrasing.
My main concern is that, if you are practising several hours a day, as I used to do, there will come a point where your efficiency will decline through fatigue and loss of concentration. Shorter bursts of effort, say up to an hour at a time with at least a 20min break is far more beneficial, and each shorter session should have a different focus, whether excercises, different pieces, sections within the same piece etc I have probably repeated a lot of what has been said, but I have learned a lot from mistakes I have made with my practise habits over the last 40 years or so.