For me, these things:
0. Found Pond Boss first.
1. Went with the more expensive reputable pond builder, not cheaper hole digger. This would have meant a larger pond, less likely to leak, and would have been downhill a little more which may have had better water input.
2. Built a pivoting floating dock capable of 3' of water depth changes rather than a wishful thinking fixed dock.
3. Ladder stocked my fish, most notable the walleye should have been stocked maybe 5 at a time.
4. Skipped the black-crappie. They simply don't thrive in our waters.
5. Structure, though perch and BC don't seem to care about it as much as perhaps bass and BG.

If I had money to burn, I would drain the current pond, and enlarge it downhill like the original quote. I would guide the construction carefully, and make sure compaction was performed correctly. I would then build structure and re-stock all over again.