In my opinion, the strategy of forming a crypto-currency portfolio assumes a grammatic distribution of investment funds between several crypto-currencies. This means that you should thinkfully and consciously choose separately profitable crypto-currencies, separately reliable, and decide what is more important to you - income or reliability.
In building a cryptocurrency portfolio, you need a lot of time because if you do have a lot of time and patience then you can have those two which is reliability and income because there is no good cryptocurrency in the market that is all about reliability without income because all the coins that are in the top rankings are reliable and also profitable.