S28 and 41

I don't know why you used an Eb Horn in this piece.  The piece is clearly in F and back in the classical period in music history, when horns didn't yet have valves it was customary for the horns to use crooks to be tuned to the same key that the piece is in.  Most of the notes you've written for the horn in this piece are easily playable (i.e. part of the harmonic series in the key of F) by an F Horn but not on an Eb.  In order to play the notes you have written the horn player (playing on an Eb crook) would have to stop the horn to for example, play the F#'s you have written in meas. 7 & 29.  The written A's you have in the staff are also difficult to produce since the partial that naturally occurs in the Eb Horns harmonic series is a slightly flat Bb.  But for F Horn that note would just be a G (both the high one and the low one) and could be played open with a clear tone.

There are a few issues with the rest of the instruments as well.  Sometimes I am hearing an oboe sound, but there's no oboes anywhere in your score.  Also, you clearly meant for this to be played by a string orchestra, but the patches you're using are the individual violin, viola and cello patches (one instrument per part) which makes this sound like a string quartet with winds.  Make sure you choose "Violins" instead of "Violin" when picking your instruments to get the full ensemble sound.

Now about the music.  It was customary in symphonies of this period to have at least 2 instruments play in pairs for the winds, to help sometimes fill out the harmony.  I see you've written the main melody in the Violins and some harmonic heterogenous lines for the Flute.  That's a good idea but it makes your orchestration sound really bare when the Flute and Horn don't have a partner to harmonize with in their own instrumental family.  Harmonizing between different instrumental families isn't as effective nor full sounding because the timbres between the strings and winds are unique.  Each part of the orchestra (strings, brass, woodwinds, percussion), in a sense, exists within it's own sound-world.

I hope some of that was helpful!  Thanks for sharing this symphony attempt and keep composing!

Thanks a lot your feedback helps me a great deal