How Can I Improve My Writing - Tumblr Posts

HELP!! HOW DO I GET BETTER AT WRITING??

I'm currently trying (and struggling) to write a story about a kid who befriends an android disguised as a human child sent by aliens from a planet far far away to gather information on earth. It's supposed to be set in the early-mid 2000s and overall just a fun time!

Slight problem though, my vocabulary is quite limited and I'm having a hard time making my writing interesting. All my writing experience comes from writing short stories based off pictures or sentences in English class.

I'm going back to my fanfic phase so that I can take note on writing styles and vocabulary but I'm unsure of what exactly I should be taking note of.

If you have any advice on how to get better at writing that would help so much!!