Your writing isn't bad, but your instrumentation and mixing leaves something to be desired. I feel like everything is sort of laying flat. I think there is a chorus or flanger on your high strings. It's really sticking out. The piano is also laying too loudly on top of everything. It should be spaced out, not in the way of all the other sound. Also, I feel like the low strings are too busy, or just too loud. Needs more 808 bass.
You could be doing a lot more work playing with those hi-hats than I hear here. It's just really long, and a lot of repetition of the same. For a beginner though, this is a good start.
I recommend learning how to use a master limiter on your mixes. This will solve volume problems without the risk of distortion. Compression is your friend.
Some good tools for trap are Massive, any 808 based synths you can program and get a good low end sound from. Sometimes I use distortion on my basses to make them stick out. If you don't have access to a good synth, there are VSTs like Alpha Sampler that you can plug in trap or hip hop 808 samples into and write them that way. Pay particular attention to the most common rhythms in this genre. Listen to other artists. Imitation and emulation can lead you to develop your own definitive style.
IMO, you should have busted out with the end of this song from the beginning. It's the best part. A lot of people would hear this and press skip. I'll compliment your fade-out though. Keep it up!