I don't trade coins though but I assume its less risky to stick to the coins that are already on top and has been traded regularly.
The great thing with yobit is that you can get free new coins to test its waters.
I concur trading is very risky though very rewarding as well and i believe that it's very safe for you to invest into bitcoins or the popular cryptos by just buying and holding the coins in your wallet safely and securely.