I was the opposite. Good results were rare so a lot of focus was on praising my effort. That meant I put in enough effort to coast, having low confidence in my results. It's hard for me to learn new things now as well.
I've take a slightly different approach. When my kid has success, I praise the effort put in to get there. This doesn't praise the kid directly (leading to inflated beliefs about how great they are) and it doesn't praise effort for it's own sake. It praises the kids ability to put in effort to get the results they want. I'm not saying it's right, or better, but like some of the other commenters here I've got my own issues in this area and it's my attempt to handle the next generation a little better. BTW to a lesser extent I apply this to myself now too.
I think the most effective approach is somewhere in the middle -- you have to praise successful efforts. The more crucial part is organizing the curriculum so that every student has enough opportunities to "win" that they maintain confidence, but "lose" often enough that they don't become complacent.
That's hard enough to do in a 1:1 setting, let alone a 30:1 classroom. I think there's some benefit to 1:1 tutoring/individual enrichment any time a student isn't smack dab in the middle of the bell curve.