More bad diagnoses come from bad setup than from bad analysis. Measurement Setup 101 is the discipline course: how to get clean, trustworthy, repeatable data before you ever look at a spectrum. It starts with the single most under-rated variable — how the sensor is attached — and shows why a stud mount reaches far higher frequencies than a magnet, and why a hand-held probe is fine for a quick check but useless for bearing work.
You will then cover the rest of the chain that quietly ruins data: cable routing and strain relief so cable-whip does not masquerade as vibration, grounding and the ground loops that inject mains-frequency hum, and the conditioning and anti-alias filtering that keep the signal honest before digitising. The course closes on calibration and repeatability — verifying a sensor against a known reference and building a route where the same point is measured the same way every time, so your trends mean something. Do this well and every downstream course becomes easier.