I have found that if a new pilot is having trouble doing crosswind landings it often due to the fact that for the first time in their training they actually have to actively use the rudder. It it is very easy to get lazy feet unless your instructor keeps after you and so it is unnatural to be in a position where constant and variable rudder application is necessary to keep the aircraft aligned with the runway centerline. When I teach this maneuver I emphasize "the keep straight with rudder" verbally reminding them to do this in the flare. The bank angle will take care of its self as the student instinctively banks toward the centerline (more bank if downwind of the centerline, less bank if upwind).
In the Cessna single engine series aircraft less flap also makes crosswind landings easier, I tell my students to initially limit flaps to 10 deg for crosswind landings.
Finally there seems to be an almost universal tendency in flying schools to approach at too high an airspeed. This especially complicates crosswind landings as it leaves the student juggling the aircraft in an unnecessarily prolonged flare