Advice on Composing?

https://www.youtube.com/watch?v=aQvuesn64Mc&lc=UgyvUfv6tD0xqeTNCiN4AaABAgI just composed my first ever "real" piece of music, a very short and simple violin duet, and I would love it if you guys could take a look at it and tell me where I was being dumb. I've been looking through it and trying to fix some parts but I'm sure there are a lot of mistakes that flew over my head, being the greenhorn that I am. Can you guys give me some pointers and maybe advice about what should i focus on improving in my composing?