Follow the advice of the chart below.
That's it!
It may seem like an overly simple plan. At first glance, it might even appear like an idiotic expectation. However, I'm of the strong smelling opinion that there's more than enough writing on the wall and momentum within the growing crypto-currency market to keep this train rolling on its historical path (the trendline on the chart) for many years to come.
Bitcoin has seen, and is continuing to see:
1.) a growing number of transactions per day
2.) a growing number of businesses (mostly start-ups) that transact solely in bitcoin (e.g. OpenBazaar), or make a high (increasing) percentage of sales in bitcoin (e.g. JM Bullion)
3.) continued growth in number of registered users on bitcoin exchanges like Coinbase and quarter over quarter growth in volume (fiat value of bitcoins traded on a daily, weekly, and monthly basis)
4.) more exciting bitcoin evolution to come in the near-term future: google "Segregated Witness" (segwit) and "lightning network" for more on this.
I could go on and on, but you get the point.