I presented a lot of evidence for this conclusion in The Wave Principle of Human Social Behavior . The first thing to do is to start watching market plots closely. Label and channel the real-time movements according to the Wave Principle. You'll gain confidence immediately if the market is in a major impulse rather than a correction. That is when I was fortunate enough to begin, so I saw what was happening quickly.
Corrections are more varied and difficult.
Yet even corrections usually contain impulse waves, so you should observe plenty of them before long. You should obtain data as far back as possible. The more information you have, the better. The perspective provided can be invaluable. The approaching juncture in the stock market is an example.