Drink plenty of water or juice at home and before boarding the plane. While in-flight, drink fluids, even if you are not thirsty. Dehydration parches your throat and nasal passages, which will have a hard enough time from the smoke soot. Regarding prescription medication, if you are traveling in different time zones, make sure you take your medication according to the number of hours between doses, not by the time on your watch. There is a good chance you could either overdose or underdose.
Most people instinctively exit a plane the way they entered.
Make sure you know where the closest emergency exits are. Those sitting in exit rows are crucial to everyone's safety. Make sure that those sitting on the exit rows speak and understand English. Removal of the emergency exit window is an important first step in crash survival. Be grateful for the tight leg room.