What are some of the common problems pilots have transitioning to taildraggers?
The biggest problem can be summed up in three words: rudder, rudder, rudder. Too many pilots have grown accustomed to being reactive with their rudder inputs--waiting for the airplane to do something, then responding--or worse, actually bracing their legs against the rudder pedals, especially during landing. The key in a taildragger is to be proactive with the rudder. To be light, loose, but active on the rudder pedals all the way through the takeoff and all the way through the landing.
The second problem concerns the elevator. Pilots flying tricycle gear airplanes tend to relax back elevator pressure instinctively during the landing roll out. In a taildragger landing in the three-point attitude, relaxing back elevator pressure reduces directional control, thus making it more difficult to keep the airplane straight during the roll out. The key in a three-point landing is to hold the elevator control fully aft during the entire landing roll while actively using the rudder to keep the airplane aligned with the runway.
The third problem appears during wheel landings. The key difference between the three-point landing and the wheel landing is sink rate. Successful wheel landings require minimum sink rate. If the airplane at all settles, falls, or sinks toward the runway in the last few feet, a wheel landing will be difficult or impossible. And if the pilot flinches and applies back elevator as the main wheels touch down, the airplane will rebound into the air. At this point, the pilot needs to react quickly and efficiently--either convert the landing to a three-pointer or add power and execute a go-around.