What is the most important technique/lesson you have learned? I am looking for the one that had the biggest impact on your knitting.
For me it is the Continental Combined style. For those not familiar with what Continental Combined style is, have a look at this video that someone made:
Since I finally fully grasped the combined style, I have had a complete different understanding about all stitches and why they are done in a certain way.
It also changed my knitting speed, especially for ribbing. Now I am able to knit any ribbing really fast. This also means that any other stitch switching between knit and purl, for example seed and moss stitch, I am able to do fast.