The best way to keep your coins safe is to keep them offline, using an encrypted USB or a professional crypto dedicated hardware. If you still want to use an exchange we do recommend you to only use trustworthy and well-known exchanges.
Do not forget! Do activate the 2FA function whenever it is possible. If you want to be even safer, split your portfolio trough 2 or 3 such platforms. There is a near zero possibility all of them to get hack in the same time.