You are a bit wrong about your profit. If you invested $20k and eventually got $40k then your profit is $20k, for you can't count the initial investment in the profit. On this forum it's more popular to right profit in a coefficient manner (e.g., you have 2x profit). If the initial investment is $20k and you seek for $1million than you are targeting an enormous 50x profit. I don't say it's impossible, but that won't be easy for sure. So far your main mistake was selling out too fast. I think you should go for long-term investments and simply buy the most promising (and most famous) coins even if for now their prices might seem high. I am sure they'll give you some nice profit anyway if you hold them enough. I suggest buying ripple, iota, monero, litecoin, bitcoin, neo, eth. If you're willing to try more risky things then buy electroneum as well. Good luck!