I’ve been working with cryptocurrency not for so long, I mostly invested in BTC, ETH and Nano. A loved the latter because of quick payment making without commissions and transactions are confirmed almost immediately. But now, I consider new projects with promising technologies.
The key principle for choosing is market cap: you can make really a lot of profit only on popular coins. Another factor is issue, the fewer coins there’re, the higher the demand for them will be in the future.