As in sport the players tire but the spirit of the game continue to exist ,similarly investors are not to panic from declining prices of BTC as It will continue to dominate the crypto market in future ,so nothing to worry,prices if falls may rise again.Do you agree with me.
we don't stay here if we don't agree with you. Market will recover we all believe in that. But we don't know when will happen. It is most important thing is timing for all of us. Some of us need cash

I'm new to crypto currency and I can't tell the good ones from the bad ones.
Do you know where to learn such knowledge. Maybe some rating platform?

It seems that you are expert here

You can get knowledge by using the forum fully, where their are so many experience users are their who gives you full knowledge about this market. It is a known fact about trading is that if you believe in market and know its performance then just go according to it. Bitcoin have always gone ups and down, only matters is the time how much it takes and how much traders can be patience to earn profit. Only the impatience traders are getting panic as they enter this market thinking of earning profit soon.