I wonder why you repeat so much in measure 38 to the andante. I get that you're trying to transition, but just repeating the same thing over and over, even if you change the tempo, it's as if you didn't know what to do to change into the next bit. But in general I think some of the transitions are a little underdeveloped. This is first evident in the transition to that segment (Moderato measure 31 onwards.) Which out of nowhere gets a really thin texture, as if you make a kind of general pause but not quite.
Let's take your inspiration, the Rachmaninov piece, as an example. When he transitions into the Meno Mosso pianissimo bit with the arpeggios, he had already fully completed the initial idea. This is the reason he can allow himself to just go into something totally different. You have to remember that Rachmaninov was operating under a very romantic framework of form. That is to say, he started the prelude out as if it was the exposition of a Sonata, so when the second part comes, you could easily see the connection to it being the second theme of the exposition in a sonata form. Don't be fooled by the name of a piece, as the majority of the concepts of form from that period (and specially composers that adhere to the late classical-romantic structures) all work in a similar fashion. Likewise, that second theme is also fully developed before he does anything else.
When the accelerando comes, is where you would expect the development section of the sonata form to begin, now that both themes have been exposed long enough to be "locked in memory." However, since this is a rather short prelude, he doesn't do AS much of it, but he does still do development, if only mixed in with the actual reprise and end cadence. It's obvious that if this were an actual sonata movement he would have taken much more time to elaborate on that, but instead he kept it relatively short.
But the main thing to take from all this is that the prelude is very simple in terms of structure and it doesn't have a lot of musical material. Indeed, you can roughly label it as A B A, though I'm not a fan of lettering it like that since that last A isn't really A, but more like a pseudo-developmental reprise and end cadence that somewhat resembles A. It's also important to recognize that transitions vary greatly depending on what's being transitioned. This is the same difference between a modulation inside a piece and a transition between two different movements of a bigger work. Think about how those things operate and why.
Now going back to your piece, you go through a bunch of changes and a lot of different material but you don't stick around long enough for it to make any difference. I'm not saying you should outright copy Rachmaninov, but think about why people structured their music that way and specially think about how long things are in those pieces. How much of it is actually lingering on a single concept before moving on. I think that'll help you strengthen your musical ideas in the future.