Long before, but especially since the 911 airline hijackings, people are weary of airline travel. A lot of people want to know they are riding on a safe airline. Airlines for the most part are safe, and the most dangerous factors usually include flying conditions (such as storms, or mountain terrain). Proper planning of destinations and good airline security lessens the chance of terrorists, bombs and hijackings. Of course there are always the rare occasions that something horrible will happen, but it is said to be 100s of times more dangerous to travel by car than it is by plane. That statistic should be comfort enough. The International Aviation Safety Assessment is a guide to which countries meet the airline safety checks, not the airlines themselves.
The majority of airline accidents occur on take off and landing, so you should try and book flights that don't have a stop over destination. That's a good preventative measure right there, not only that, but you wont have to sit and wait to change planes half way through your flight. Another good way to fly safer is to know that larger airplanes have stricter rules and the passengers have a better chance of survival if the plane should crash, so you might want to consider booking your flight with a large airplane of thirty or more passengers.
Like anything else, always be aware of the closest emergency exit, and consider keeping your seat belt on at all times while seated. This is especially true if you are nervous about turbulence; which is often unexpected and can cause injury. You should also keep anything too heavy out of the overhead carrier in case of turbulence. You don't want anything to fall on you or anyone else. Also, allow the flight attendants to handle your hot drinks and food as they are trained to handle it and can safely manage giving it to you. You don't want to be walking around with a hot cup of coffee in your hand and have some turbulence spill it all over you or someone else.
As far as airplane crashes go, they are very rare. However, if the incident should occur, try to remain calm and listen to the flight attendants. They know how to handle situations and keep you safe. Often the very front or very back of the plane is the safest. Sitting close to the wings is the worse place to sit. If the plane wings get torn off in a crash it could tear the fuselage and cause death to anyone near the carnage.
But don't worry, airline travel is safe. I wouldn't worry too much about it. Just believe you will live and you don't have anything to worry about.