Read Play It Again by Alan Rusbridger. It does a good job of capturing the myriad struggles that amateurs have with this piece. I would recommend learning all your scales and arpeggios thoroughly, practicing sight-reading on a daily basis, and playing through and learning as many of the Chopin waltzes and nocturnes as you can.
Additionally, find yourself a teacher who can work with you on your musical judgement and advanced technique, such as that required to play Chopin's Preludes, Nocturnes, Polonaises, Etudes, etc. I would honestly not recommend playing the Ballade seriously (besides some of the slow lyrical sections, which are undeniably gorgeous and not too difficult) until you have studied several Chopin Etudes and can perform at least one confidently in front of an audience from memory and at full (or nearly full) tempo with very few mistakes.
Additionally, I would recommend Op. 10 No. 10 and Op. 25 No. 5 for their particular study into many of the same hand shapes that are required by the Ballade. I would also recommend playing Bach--start out with the two-part Inventions (No. 8 first, then No. 1 and No. 15), then take on a Sinfonia, and finally a Prelude and Fugue. This will help you to develop your hand and finger independence, which is absolutely critical for playing the Ballade well, as there are many passages within the piece that feature similar polyphonic (multi-voice) writing that will fall flat in the performance if the notes are not held correctly (either too short or too long).
Make no mistake, the G minor Ballade is a horrifically challenging piece from start to finish--certainly not impossible to master for an accomplished pianist--but nearly so for a beginner/intermediate, for whom it can take years to finally play at tempo. Nevertheless, it is a worthy goal to play the piece, and while you develop your musical taste and technique to accommodate the work, I recommend you get to know Chopin's style and sound thoroughly, as well as that of J.S. Bach, Mozart, and John Field, all of whom Chopin to enormous inspiration from. I recommend listening to Rubenstein, Zimmerman, Cho Seong-jin, and many others who have mastered this piece.
Good luck in your studies!