Please see the disclaimer.
The last post was about the best way to avoid being deceived: follow the Prophet. However, the Prophet will not tell us everything. He will certainly tell us everything we need to know to act for ourselves, but we have a responsibility to act and think for ourselves.
We must educate ourselves in everything. In this highly-specialized world, we need to have our specialties, but we also must be generalists. This is the best way to avoid deception when the Prophet gives no counsel.
Perhaps you hear about a new study with a finding that seems a little suspicious. Do you know about experimental methods? Do you know statistics? With those tools, you can read the study for yourself to see if it has weaknesses. If it does (and it appears that most do), you can remain skeptical instead of blindly following the crowd.
In fact, even when the Prophet speaks, you can use those skills to think about why he gave the counsel he did. You can go to the Lord and seek confirmation, which will always come, if you listen with real intent.
By learning as much as you can about every field, you can have an instinct about whether you are being lied to or not. Such an instinct will be invaluable in the Last Days.
But in order to have it, you must always think for yourself.