How to make profit during a cryptocurrency / Bitcoin (BTC) / Ethereum (ETH) / ICONOMI (ICN) rise

Since a few years I am a passionate follower and investor in Cryptocurrencies.

I started with Bitcoin (BTC), made some profit, found Ethereum (ETH), made even more profits and am now invested in ICONOMI (ICN).

Crypto is exciting and a booming, fast moving market. It moves up fast and hard, crashes again, but in general in a uptrend...

But what is a smart way to take profit?

After some painfull mistakes, the biggest around the DAO hack with Ethereum (I had invested a lot in the DAO and ETH, should have taken more profits during the rise before the hack), I started looking for a good strategy to:

Take profits during a crypto rise, but not sell too much too early (nobody knows where the top is)

The main issues: