According to Osho, nothing extra is required—entering trance arises from total, one-pointed concentration on the chosen object or act. When attention becomes complete, thought subsides and trance happens by itself. The key is undivided focus, not effortful suppression of mind: simply keep concentrating until your awareness is wholly absorbed, and the shift occurs.
Just put all your attention on one thing until it fills you completely, and thoughts fall away on their own.