Agreeing with Kalama the Facebook group has a wonderful set of informational posts -if you are comfortable finding info on that forum. Maxine Rosenthal's books are super helpful. There are several good videos that are searchable on YouTube...I think a visual of how to get the 6 layers of fabric aligned is very valuable:
https://www.youtube.com/watch?v=xK_pB79uzHI That was one part I really needed to *see* before I did.
One lesson learned on my first obw was that after I sewed my half hexagons into strips, or vertical rows, I kept the rows pinned to my design wall for too long. It started to get pretty stretched out on the bias sides which I noticed when joining rows. I wouldn't sew then leave the 'rows of hexies' pinned up for longer than necessary. Place them down on a table, marked with a piece of tape/however you mark rows before assembly.