I think that Shadow Techniques is good for memorization, but you need to practice on people for application. The good news is this means you can work on your memorization while you're doing shadow techniques, and then focus solely on application when you get together with a partner.
Now, when practicing with a partner, here is how I help them practice (phase by phase):
- Basically do the technique for them so they know where I'm supposed to go
- Let them have control so they make me go where I went in phase 1
- Passively resist them to make sure they have the correct leverage points to continue to do what they did in Phase 2
- Actively resist them if they mess up so that they can figure out what to do when Phase 3 doesn't work
- Sparring, experimentation, and variation
By yourself, you can't move past Stage 1 or Stage 2. But sometimes you still need to be there, to help with the muscle memory and memorization of your techniques. Especially in a school like yours or mine, which just says "White Belt #8" instead of "Z Lock".
Another way I've used it is to get myself out of trying to make the darn thing work, and get myself into the mindset of at least memorizing the steps I'm supposed to take in an ideal scenario. I was in a group of 3 and got a lot of critiques on my technique from my Master. After I applied those critiques, I broke off from the group and meditated by myself to ingrain those better into my memory.
I put off practicing the application, because if I focused on making them work, I might only remember one or two things. This way I could remember them all (at least long enough to go home and write them down) and then I could come back next week and apply all of them.