Whilst poor weather is the most obvious big killer, I'd say the most likely cause of an accident if you're starting flying, especially in an R22, will be messed up engine offs then rolling the acft on landing, and loss of control in the hover. Then once you're off with your new licence, heavy landings or worse from misjudged take offs and approaches when you're too heavy, or lose (often translational) lift, usually through unrecognised tailwind components.
Just what seems to crop up the accident reports most!