I think if you'd invest a few months ago in Bitcoin it would have been a great idea. Not, however, what I hear a lot of people doing: Putting a lot of their money into it (as in even selling their house, their kids' toys, etc.), because that's idiotic.
However, keeping an eye on the currency it has increased in value significantly, but as it's going now crazily skyrocketing upwards?
Take it out. Don't panic, just take out your profit.
I'm giving it a week to at most a few weeks before it comes crashing down.
Also Bitcoin follows the value mostly of the currency you invest in with. So you invest with USD? It seems to go up very fast, but investing in a more obscure currency like ZAR? It's actually halted it seems.
Eitherway, investing a certain amount of what you have is always a good idea, and in multiple various companies, not just one. Look and learn at how currency overall behaves, when is it usually the 'strongest', when does it have its ups and downs, basically?
Also take a good look at what news there is on the company and the places the company itself invests in and such, so you can figure out what might happen next. (For example a fusion between companies might increase the value of your investment or lower it.)
Usually when something new is introduced in the investment world, it's new, it's hot. It'll thus gain value. But once it crashes it almost never regains the value it would have once had at its peak and after an even longer time in a lot of cases there won't be extremely high ups or extremely low downs either.
Investing is mostly psychology rather than math. You won't indeed get far with formulas and stuff, but by knowing the market and how people behave and respond, this will determine the value of the investment.