1) Watch this to get a good idea of what the "fundamentals" of art are:
https://www.youtube.com/watch?v=piKV5nXL-C4 And remember what Pablo Picasso said: "You gotta learn the rules like a pro, so you can break them like an artist."
2) Read Loomis, Perspective Made Easy, and other reputable art books to get you started.
3) Draw a lot from life. Do still lives. Draw some scenery. Go do some figure drawing. And then try to apply what you learned from all that into drawings from imagination.
Study (i.e. draw something from reference) → Draw from imagination → Repeat.
4) Always think critically and continue to seek out information and advice on your own.