Thanks for the article. I have learned this to be true with dry flies... most recently last weekend. Until I figured out how to get an effective drift, the lie where fish were rising had me facing a slow upstream current, next to a faster downstream current, next to another slow upstream current (so slow it was almost slack). The only way to float through the sweet spot was to position myself directly downstream (10-12') from the closest upstream flow. A slack-leader cast (line mended to one side) only drifted drag-free for about 5 feet, but I was able to hook three fish (and miss several others) from that one spot. I was just happy to be able to strategize it while I was actually there - unlike the countless other times when I'm off-the water later thinking, I should have tried this or that.
Yes, having a drag-free drift is of the upmost importance, especially when dealing with steelhead in clear water that are used to 70ft. of water over their heads. I mend initially after I make a cast upstream to get a good drift going. A friend that I fish with and mentor (more so make fun of) just got into indicator nymphing and I was teaching him about it and how to get a good drift. He's picking up a good amount of fish now (out-fished me by one yesterday) and is picking up on the subtle nuances of indicator nymphing (his mending still needs work). He's an older man and set in his ways so some things are hard to teach. I will admit I am not the best teacher as I am very literal when explaining stuff and will critique the person I am teaching immensely. My reasoning is that the fish don't care about your feelings, they only judge an angler by their skill, so I am blunt and don't sugar coat stuff.
Today I think I will teach him dry/droppers, to include the importance of keeping the dry actually dry. I'm thinking a size 14 caddis, black body and tan wings will be the ticket. I will trail this with a bronze beaded PT size 18. Let's see what we bring up! I am getting bored of nymphing and the trout were definitely taking caddis yesterday.