>>13262
I've seen some act like Decimate is a good way to reduce overall poly count, for example. Which isn't true at all. It destroys your edge flow, and even the Un-Subdivide mode doesn't help much because the program doesn't care about which edge loops you need and which you don't (just don't use so many subdivisions in the first place). Many also act like you can just leave copied weights as they are, which is bullshit.
A ton of tutorials go "Ok now we just add a solidify modifier so you don't see any gaps on the inside" which is utterly fucking stupid. Cover your gaps selectively. The inside of a skirt is one thing, but the inside of a muscle shirt can be left just how it is.
I saw one person who made a tutorial on creating a house and left the actual walls as single-sided planes. There's a ton of terrible shit.
Look elsewhere on forums on places like Polycount and CGTalk and often they'll direct you to a specific YouTube video (essentially straight to a good one) then you can look through that specific person's other videos. But searching YouTube and grabbing whatever comes up is a mixed bag at best.
It's also important to pay attention to whether the person works in game modeling or CG/rendering, because there are different practices for each (though most will translate between them).