simply holding might work based on past record. if you bought in oct 19 2011 you got a bitcoin for $2.27 so now you have 100x your buy in price.
lets assume the growth rate flattens out and it takes now 3 times along to go up the same way means holding for about 9 years.

considering bitcoin adoption is still effectively nil ie demand is miniscule it is entirely possible to get there and may be sooner. Sure bitcoin is essentially an all or nothing stock but if you think it is going to die you would not be buying at all  - but if you are a believer then things look bright.

be patient if you are only buying in now