There are way more than 50 awards online so this will be pretty easy. Here are a few tips:
-During matches stick to one class to get awards for that class then change to another class and get awards for it too.
-Join a squad a work together as a team! There are several awards for teamwork and teamwork will make your Battlefield experience more enjoyable as well!
-Kill streaks in vehicles will unlock awards too, if you are not good at driving/flying in Bad Company 2, find a friend to drive for you and get in a gunner seat.
You should have no problems earning awards on your path to ranking up online, but if you do check the awards section in the main menu and see which ones you are missing and it will tell you how to get them too!
Stars earned from weapons and vehicles count towards this as well. Stick with a specific weapon or vehicle and you will get stars for using them.
There are 40 pins, 50 insignias, 21 vehicles, 41 weapons, and 11 gadgets, and 4 vehicle types.
(each weapon, gadget, and vehicle type have 4 stars that count separately)
Pins are generally easy to acquire and insignias take quite a bit longer with requirements like 500 kills with certain weapons.