After a couple of years, this guy joined our dojo who helped me, and suddenly it all made sense.
If a beginner can resist, you do have some problems, because they shouldn't know where to resist.
1. From ai-hanmi katatedori, say his right on yours, move in so his neck in within reach of your left hand. Flip your right face up so you can bring it to his right elbow, catch his elbow (with your thumb down) and push it away from you and into him. This generates a torque that pushes him off balance. If he comes back around when you take his neck, it's easy. If he resists, he should be unbalanced enough that a gentle tug behind will bring him down, and he'll follow next time so you can do the complete technique.
2: With your thoub down, when you come around (taking their neck) you can bring people down really easily to their knees through bringing their elbow down. Of course, if they don't know to try and get up, there's not a lot you can do.
3: At the final throw, remember what you're doing. Don't try and push him over, go up at the front of his head to force the back down.
Pressure point etc. are all well and fine, but you need to be able to unbalance without them too. Some people don't respond so strongly to pressure points, but they're always subject to gravity.