Most likely you won't be very profitable at first, and with that in mind I would say the single most important thing is good money and risk management to keep you in the game while you continue to acquire the knowledge necessary to trade profitably.
Of course what you risk is up to you, but it can only help to risk lower amounts while you learn the ropes and increase the risk to a point you're comfortable with as you get better and better. I really don't see the point in throwing away money by risking a lot, as you're almost guaranteed to be a loser for the first few weeks/months/years even, but you still want the psychological benefits of learning to trade a live account.
Of course what you risk is up to you, but it can only help to risk lower amounts while you learn the ropes and increase the risk to a point you're comfortable with as you get better and better. I really don't see the point in throwing away money by risking a lot, as you're almost guaranteed to be a loser for the first few weeks/months/years even, but you still want the psychological benefits of learning to trade a live account.