My third time compose

This my the 3rd song i write.. Pro pls help me to complete myself..Thank you ~

1. Too short. You have a good melody, supported by decent chords, so there's no reason not to expand on the theme, because otherwise you haven't written a piece so much as you have a melody. 
2. Your first measure should be a pickup measure, not a full one with rests.
3. Your timpani part is borderline impossible as written. They only have four or maybe five (rare) drums and the huge span of constantly retuning notes will either not be played or played with a bunch of slides which I don't think you want.
4. Your vocal part should have a designated vowel or lyric set with it.
5. Sometimes your piano left hand and right hand intersect. Avoid that. In that same vain, avoid crossed timbral voices as well, since that happens more in your piano than anywhere else.
 

Thank you so much Monarcheon. I will remake this song and try my best in the next song. Thank you !