“Try harder” is the worst kind of plan. It’s basically not a plan, a small resistance to planning. An anti-plan that signals virtue but instead reflects shallow thinking.
Don’t say “try harder”.
“Try harder” implies that folks haven’t been working hard enough. It leaves the door open to come up short again, for all the same reasons, with little to show for it.
It assumes folks can throw themselves at a project/problem/task even harder without consequences, like exhaustion, burnout, diminished performance, letting important part of their lives suffer, etc. Not only that, but it’s a terminating thought, the kind of thing you can say, and few people will say “well no, we can do better than that” and end up not solving any underlying issues.
“Try harder” is trying to avoid a tough question: why did I/we come up short last time? “Try harder” is resignation to learning nothing and plowing head-down anyway.
Try harder is literally working harder, not smarter. I highly recommend the latter.