expect BTC, and ETH, how I can recognize some other good coins? How I can recognize when is the right time for buyng and sellig crypto to make most of trades profitable?
Basically you can stick within bitcoins and ethereum rather than looking for new opportunities. I agree that when you are not trying new coins, you may miss out some of good coins but if you invest into at least 10 different coins then your chances of finding one 10x return-able coin will be possible; so the risk reward ratio will be 1:10 and if you are ready to take that level of risk then you may go for investing into new coins by leaving off bitcoin and ethereum.
Is it possible some how exploting some coin and be sure this coin can make 10x, 20, 50x,... in next months?
Never expect quick profits. You may invest into bitcoin and any other coin when the entire crypto space will be entering into bearish mode but you need to wait for at least 3 to 4 years to see some significant growth of your capital. You may get quick profits this year but that is not the case for all the times in this crypto space.