I saw a great talk at the London Cryptocurrency Show that included a discussion on leverage. In a nutshell the presenter said that he sets up his system of trading according to very strict rules. He then applies these rules for a while and makes sure that he is satisfied that the system has potential to turn a profit.

At this point he determines whether he wants to include leverage and how much. His view was that you should be able to make profits without leverage before factoring it in to your system.

But even with this advice I wouldn't use leverage. There's plenty of risk available with crypto without ramping it up!