Ask your team “what’s the weakest part of my plan?” and then genuinely thank whoever answers.

People can see the flaws in your plan long before you can, and they will keep that to themselves unless asking is obviously safe. The question only works if answering costs the speaker nothing, and that gets decided entirely by what you do in the ten seconds after they finish. Defend yourself once and nobody tells you anything for a year.

Ask it directly and specifically instead of inviting general feedback. When the answer comes, thank the person by name and write the point down in front of them. Change one thing as a result, then say which thing it was.