Could u give me some advice then on the g minor prelude?:
How fast do u play it? Do u play it at 108 as instructed?
Do u use the pedal for the staccato notes?
Do u use the pedal for the octave scales in the 2nd section?
I usually play it at the given tempo, but some days I like to moderate it... It can be painful if you are not ready. Most pianists of today play this music slightly slower or at the speed. Gillels played it faster, as in Rachmaninoff's first recording. I try to use the other recordings as a reference, since Rachmaninoff himself played the two recordings at different speed.
I try to keep the beat up on the first section, gradually increasing the sound to the end, as it is repeated. At the second section, I try to make the tempo a bit faster.
For the staccato notes on the second section, I lift the pedal up and down faster, so I don't overuse the pedal and keep it at its marcial characteristic. The only one I play staccatto is the chord just before the octaves. I use full pedal on the octaves, and when I come to measure 21, I play the staccatto notes as indicated and use pedal on the octaves. On measure 23 I pedal the quick octaves that follow. I use the staccatto properly on measure 31, and on. When the second section repeats, I play it faster, louder, with more pedal. Although they are marked exactly the same, I think it is a matter of musical taste to variate it. ( I like to bring the second section back stronger)
The pianist Valentina Igoshina does the total opposite... She play the big chords with pedal, and the octaves she play staccatto... I thought it was odd, but it sounds good anyway... Again a matter of musical taste, which you will probably modify after memorizing the piece.
Other of my advises are: Throughout the Prelude, you should practice slower, and emphasize the chords of BOTH hands... When I first practiced the Prelude, I was playing the three fast right hand chords right, but on the left, I was missing some chords because of the speed, and because I had to get my left hand used to play the repetition... That is why I recommend the study of this with separate hands. This Prelude can be exausting for the left hand, especially at the Un poco meno mosso section, and a good study of it requires time.
For me, was very easy to replace the composer's own marks after I had it memorized. So I suggest you to analyse the partition very well at all times. Practice all bars individually, to eliminate all problems. Perhaps the greatest problem for me was the octaves passage at the second section. I suggest the study of those lifting the hand high everytime you play an octave, and at lower speeds, different rythms, etc.
Always study carefully so you don't hurt the right hand, as I did.
I hope this was helpful, this is one of my favorite pieces, if not the favorite...

Enjoy practice

Sincerely,
Mario Barbosa