Crypto is an entirely different investment animal. It is ruthless and unforgiving considering how many scams and junk coins are out there. The only thing you can do is look into the individual coin and look for a reason to why the coin would have value.

Bitcoin is basically digital "Gold" and all other virtual currencies are priced against it.
Ethereum / Waves / Stratis etc are utility tokens meaning you can create an ICO on their platform as well as create smart contracts.

Then you have specific coins such as what madfranks detailed above who only exist to fill a particular niche, the potentials growth/loss can be equally measured in a lot of these coins.
Tezos comes to mind. Full of a lot of hype, but ended up breaking down due to internal strife within the board. Now there are class action lawsuits from investors who want their money back.

So it really boils down to how you would invest in a stocks, research the company (coin). Measure it against what it is attempting to achieve, check its competitors, check its developers and if possible look into the developers past and see if there are projects that he/they walked away from and abandoned.

If you're looking for long term, you can't go wrong with either BTC, LTC, or Ethereum.

If you want to gamble and can buy a bunch of shit coins and sit on them to see how they perform. This guy did a project at the begining of the year, using $50, and bought the lowest value (at the time) coins (100 of them to be exact) and is just sitting on them.

He's openingly publishing his results here: https://cointracking.info/portfolio/TGPCE2018/

He's already up over 4x his initial $50.00 investment and he admits he picked the coins at random and if they were less than a penny during the initial purchase.

So it's a crap shoot...... lol