It sounds fairly classical, but somewhat lacks directionality; and the harmonies are a bit clumsy.
Apart from improving your harmonic skills, check out Caplin's Classical Form: A Theory of Formal Functions for the Instrumental Music of Haydn, Mozart, and Beethoven
Google it and I'm sure you'll find a pdf.
Anyway remember you must shape the 1st mov. of a sonata in "sonata form".