To do something, as opposed to trying it, means to succeed rather than fail. However, we often do not have control over whether we succeed. Doing or trying is not an option. We do have the option of whether to keep trying, or give up. I think Yoda means in this context that Luke should never give up, but keep trying. However, should one never give up? It depends on what one would be giving up on. There is only a finite amount of time in the day. That time must be spent well. It is perfectly acceptable, and in fact necessary, to adjust one's effort as new information comes to light. If I set about trying to move an object with my mind, being without Force powers, should I "do instead of try?" Of course not, because that wouldn't work. Similarly, some things do not work no matter how many times they are tried. Or they simply are not worth the effort after a certain point.
I would say that Yoda's advice is only good advice when talking about things that absolutely must be done. In Luke's situation, saving his friends was a vital imperative. But this should not be applied to everyday activities. Perhaps one could apply this to goals such as advancing one's career, but do not apply it to specific ventures such as a job or a business idea, because committing to those will often result in failure. Instead, be certain about your vital goals but flexible in your methods.
I don't get this. Is this some argument against parents telling kids, "You were a winner for trying!"? Well, I see the middle ground as being right there. I mean, obviously, some applause should be for trying, but not as much as for winning. I mean, if that wasn't the case, people wouldn't get justice for simply avoiding things totally (case in point: The guys who didn't try out for the team).
