The other day, someone asked me what to present as a uniqueness of Yoshinkan.
Having done a variety of aiki styles in the past, I would have to say that apart from the usual things everyone says (focus on practicality, efficient motion, mastry of the basics, etc.) there are two things that really stand out in my mind as being strongly emphasized in Yoshinkan (at least more than in other styles I have seen): Knees and Elbows.
In Yoshinkan, the knees are critical. It is precisely the use of the knees that allows us to start Uke's motion moving and prepare for the shifting of our hips and body weight. When we fail to use the knees, we end up disconnecting our hips and are forced to compensate with strength of the arms instead of strength of the hips/whole body. Knees help cause Uke to cross the centerline in techniques like Shomen uchi Ikkajo Osae 2 and knees help guide uke to the mat without letting our body weight come up. In short, they are a vital connection of uke to our hip and to the floor, and anchor and a lever to move uke by shifting our weight. Without the knee movement, however, we cannot transfer the hip power efficiently (if at all).
Elbows are another key differentiator between Yoshinkan and other styles.
In Yoshinkan, we like to control Uke's balance through controlling uke's shoulder, and one of the most effective and important ways to do this is via Uke's elbow. The circular "rowing" motion of Ikkajo and Yonkajo are both specifically designed to use the wrist to elbow to shoulder pathway to control uke's body, and Yoshinkan is one of the few styles that actually grabs the elbow to manipulate it (many styles focus on wrist more than elbow and fail to connect to uke's shoulder as a consequence). Of course, techniques like hiji shime go without saying that the elbow is a central part of the technique.
One of the best places to work on this is during the basic tai no henko and hiriki no yosei movements, which are specifically designed to help us practice these two vital points. I suggest doing the motions slowly, paying particular attention to how you use your elbows and knees, since these will manifest during all of the other techniques.
So in closing, I suggest specifically visualizing the movement of your knees and elbows before training, and see if it doesn't tighten up your technique and give you a greater sense of control, which is what Yoshinkan is all about: control of yourself and control of Uke.