Electrocardiogram: Difference between Atrial Fibrillation and Atrial Flutter
A-Flutter will have discernible waves that can be counted, usually. The R-R interval will be regular or maybe slightly irregular if there's a variable conduction block in the AV Node. A-Fib will ALWAYS be completely irregular without discernible pattern.

You can also modify the position of your limb leads. There is an EKG placement called the S5-Lead that basically makes it where the QRS disappears because it's electrical impulse is perpendicular to the monitoring leads. The Atria however, become super-visible on the EKG. 

To do S5: 
Place the RA electrode on the patient's manubrium. 
Place the LA electrode on the 5th intercostal space, right sternal border. 
Place the LL electrode on the right lower costal margin. 

Then set the EKG to view Lead I