Slow down and descend "a little / slowly" BEFORE it starts to get bad... if it starts to get bad then LAND.

Although it IS possible to fly in decreasing weather conditions (see below vids) it is NOT recommended if you don't explicitly know the area; the pilots in these two vids seem to have no personal minimums:

https://www.youtube.com/watch?v=9UfThZap73Y

https://www.youtube.com/watch?v=q4_4BDqpfYc (at least this guys is low AND slow)

This is a fairly good example of taking your time and analyzing what's going on around you:

https://www.youtube.com/watch?v=jKtO4cnvNzY

Also: think about SLANT range when considering visibility.  The higher you are, the closer you are to the clouds when you're evaluating the 5 miles, 3 miles, 1 mile, etc. in front of you (so you think you can see far but the clouds up in the air are about to hit you). 

The faster and higher you are the sooner you're in the scud about to go IIMC and even closer to a tower/wires that you'd see better if you were a little lower (potentially; depending on ambient light, overcast/hills/background that may not allow wires/tower to be spotlighted by the horizon/clouds by being lower). 

If you have ANY rain on the windshield and you don't use Rain-X (or similar product) or have windshield wipers then cut your response/evaluation time in half (i.e., be even more careful, decrease your personal mins, and make a safe decision quick)

Old pilot truth, "If you are leaning forward in your seat to see better in reduced visabilty you need to do something different."  In aviation, if you become a slave to the letter of the law you are stacking the deck in your favor. If you don't comply with the rules you risk your future participation. 

And "the letter of the law" should not have allowed anyone onto his flight deck. His decision saved over 100 people that day. So much for being a slave to the letter of the law. Do what is best for the situation, let someone else mull over the letter of the law after you have done your best.

When I say follow the letter of the law I'm talking in general terms, such as don't fly in visability below the legal requirements, don't file IFR in to icing conditions etc. It goes without saying that in an emergency you do what you think is best.

As an industry we constantly get in trouble with the attitude we can do whatever we think is right regardless of the rules.

what it takes for helicopter pilots to develop judgemen these days.

Good stuff though!