Possibly it is easy for me to say but then I have had some fifty years practice, I was told and it was expected if you use a hammer gun the hammers should be in the safe down position or at half cock if you have that position at all times. The gun should only be brought full cock as you mounted the gun to your shoulder and I was expected to practice this until it became second nature. Now if you are unfortunate to miss with the first barrel and you are using a double you then part dismount the gun low enough for your eyes to help you place your thumb on the other hammer and at the same time keeping the barrels pointing skywards. Though after using the same hammer gun for such a long time my thumb automatically places its self on whatever hammer I wish to use.
But seeing that no person is perfect I have a ridge in the bone just under my thumb nail where the hammer has hit my thumb when the gun recoils on those very few and far between occasions I have dropped a hammer before it reached the full cock position. And finally if you are left with a gun and hammer or hammers at full cock open the gun before you try to lower the hammers to the safe position also it is worthwhile mentioning that guns with non-rebounding locks require each hammer to be brought to the half cock position before you can open the gun.
