Disclaimer: I am not a professional, but a hobbyist who is considering one day making the jump. Also relatively new like yourself (~ a year and 1/4 in)
Learn to shoot in manual exposure, it gives you more control over what your final image looks like. On that same note, shooting in RAW gives you even more control. When you shoot in JPEG, the camera makes all the processing decisions for you. Shooting in RAW, you get to choose how it gets processed (summed up in the simplest way I can think of). Same thing goes for Auto/manual.
HDR isn’t really my style, to me it makes the subject look grungy. To me, HDR for portraits would be acceptable for, say, a coal miner because it would bring out all the fine lines, dirt, and imperfections, giving a rugged feel to it. But I would never use HDR for a “regular” portrait for those exact same reasons. That being said though, you’re learning, have some fun with it and do what appeals to you.
Some sites worth reading for a beginner:
That’s my 2 cents 🙂