Unfortunately all you can really do is take steps to minimise the chances of it happening:

A) Craft in quiet places with few people around (like inside a house/apartment). The less people around you then the less network traffic you're sending/receiving.
B) Connect with a wired connection, instead of wirelessly. Although the problem is likely outside your house, using wired would eliminate the chance of a drop out.
C) Get an ISP that doesn't route your traffic through Level 3 (may not be an option for you though...)
D) Definitely don't try and craft anything important if there are known issues with network routing (usually Level 3...) and others are dropping off etc.

Sorry I appreciate that's not a lot of help, but due to the nature of the Internet, unless you're literally sat inside SE's network, there's a lot of places where problems could potentially pop up.