Does anything have to be done? If not, do nothing!
If something has to be done, does it have to be done now? If you can wait then you can wait for (or seek) more information.
If something has to be done now, is it possible to quickly obtain more information? If you can quickly get more information then some of the new information might be helpful.
If something has to be done now and you cannot get good information, do you have enough information to help you select which actions are most likely to be appropriate--or to rule out actions most likely to be inappropriate? When working with incomplete information you have to make the best possible use of the information you have.
If all else fails, cross your fingers, do something that might be right, and hope for the best. Try to keep your options open so you can change your mind if your choice isn't working, and pay attention so you know if you need to stop what you are doing.
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When diagnosed I bought champagne!
I finally knew why people were strange.