Isn't this gonna be the same as me scouring the internet for golf instructions?
In my personal experience, I got the most benefit from having a coach see my swing and how I play a round. He has helped me identify my weaknesses and we focused on improving these points.
Case in point, I thought my pitching and chipping was quite ok. Upon observing a 9 hole round, he said that it was like shit. Hahahaha.
He went on to teach me the proper chipping techniques to create a reliable short game. I never knew that creating spin to the ball was so easy! With a more solid short game technique, these moves were also the important building blocks for the full swing.
My coach was able to improve my scoring immediately while at the same time help with solidifying my full swing.
I don't think taking online lessons will yield such results in a short period of time. We view our game very subjectively, no matter how objective we may think. We need a trained and experienced pair of eyes to truly see what are our weaknesses and focus the efforts on these areas.
That I feel, is the best route to go.