The Sustained Investigation is an inquiry problem. Most students treat it as a production problem.
Don't invent one — find it. Read across 20–50 pages of your existing work; the question you keep circling is already there. ApoKrino Forge automates this read-across, and the free Creative Signal Scan does a first pass on 5 pages.
Visible inquiry: a guiding question, genuine experimentation, and revision that responds to what the work showed you. Technique supports the investigation; it doesn't replace it.
Trevett Allen coaches AP students remotely across Asia, Europe, and the Middle East (based in Spain, CET). Students placed at RISD, SAIC, Ringling, UPenn, Stanford.