The Essentials of Throwing.

Here is a checklist of what must happen for a throw to occur. In other words, if you meet the elements in this checklist, you are in a position to apply a technique vs. just trying to overpower the receiver. These are quite classical and as useful today as ever. This is not a procedural manual, so do not think that you will apply this list as is to every throw, it simply represents a pretty average sequence of events. All throwing has these, refined or not. The final three elements (kuzushi - kake - nage) are more or less fixed, but the rest of the list may shuffle the order or even combine the elements in a single movement. This gives you a high-level way to analyze your throwing, which in turn makes it more effective or can be used to troubleshoot a particular throw you are having difficulties with. Since there are many variations of throws, the question shifts from how to force the specific form for a throw to how to ensure that you can reliably get all components together. If you cannot name a concept, it in some capacity does not exist for you. By breaking down the elements in this fashion you will be able to see which if any are absent. As I said, in practice many of these coalesce, but it is good to realize, say, that having a grapple does not mean that you have your opponent off-balance or have off-lined to avoid a further attack.

A note on offensive throwing.

This list covers defensive uses of throwing, i.e., reacting to then dealing with an attack that has massive body commitment behind it. To use throwing offensively, only the final three elements need to be present, plus a good bit of surprise, but ambushing your opponent, most probably being a form of aggravated assault, is not something we advise on legal or ethical grounds, so we won't treat it here.

Sport rules (such as in judo) require an attack within a certain amount of time or penalities accrue. This requires a different mindset to what we have, and speed plus power are usually the deciding factors -- exactly the type of training you wish to avoid for a street encounter. This is why so often in Ultimate Fighting Competitions and similar no-holds-barred sporting meets the throws essentially turn into quick wrestling dumps. This is the best way to make a speedy frontal assault on an opponent who is very close to your own size and conditioning level. While it gets the opponent on the floor in a big hurry, it often lacks power and is essentially little more than a lead-in to floorwork, which is again something to be strongly avoided in a self-defense situation.
Here is the checklist itself.

A few sample analyses

Here I'm going to give a couple of examples to show how this can be applied.

Case 1. Bubba tries to hit Joe Bob with a haymaker. Joe Bob ducks the punch (tai sabaki) then goes for a twisting tackle (called "rhino" by barroom bouncers). To do the tackle he moves to encircle Bubba's waist (tsukuri). He encircles the waist driving his shoulder in (aiki) and while following the more or less forward movement (ju), drives his shoulder in to Bubba's mid section (kuzushi) and with a twisting motion of his own hips, knocks Bubba off his feet (kake). Joe Bob rides Bubba to the ground and lands on him (nage). Seeing this in action would just look like a nice solid takedown. No fancy martial arts, no over the top techniques, just good body dynamics. Note that the order is not the same as the list and the off-balance, yielding and grapple all occur at almost the same time.

Case 2. A defense against a front overarm bear hug. Uke grabs tori, who sinks his weight back immediately while making a double fist at his groin to avoid a knee, and putting his head on uke's shoulder, to avoid a head butt. This is tai sabaki. Uke then draws back to try and regain control and tori then follows, bringing his arms up to effect a waist hold on the same side as tori's head to do a koshi nage This is the tsukuri as well as the ju. The grapple takes effect and, for instance, tori now has his head on uke's right shoulder and his left arm around uke's right side. Tori then turns to his own right, knocking uke not backwards (the direction of travel for uke) but at at 45 degree angle to this, putting uke over one foot. Tori pushes using his arms and pushing with the side of his body, using his own head to assist as well. This is the aiki part and it leads straight into kuzushi. Tori then drops his center of gravity, launching uke (kake) and proceeds to finish the throw (nage).

Case 3. The receiver grabs the thrower's wrist and attempts to strike with his free hand. The thrower moves off -line (tai sabaki) to the receiver's outside (ju), collaring the wrist (tsukuri). He then drops his body weight moving the receiver's elbow well below his hips (kuzushi). The thrower turns his body, rolling the elbow onto the back of the hand, causing the te kagami lock (aiki). The receiver is compromised and a downward strike by the thrower effects the throw (kake). The motion continues to the floor (nage).