When faced with a composition in Presto tempo, it's best to practice slowly, preferably separate hands, (at first) to secure a good fingering, understand HARMONIC flow (or progressions) and piece out the phrasing, that encompasses articulation and dynamics.
In my own baby-step maiden journey through Tchaikovsky's "Baba Yaga" (The Witch), Op. 39, No. 20, I followed my own model above, and set down a substantial learning foundation that should bode well for playing this piece briskly once it ripens.
Perhaps my learning paradigm might help others along the way.
Play through:
http://youtu.be/2JGFYEgxNcM
Instruction
http://youtu.be/PdnYGaYuoRc
Tchaikovsky "Baba Yaga" (p. 1) is attached