The safetiest that i know is to use the faucet bonus don't spend your bitcoin from your wallet just use the faucet bonus and make some profit if you are not lucky to get large amount.. its better to stop so that you can control your self for being greed..
Many people said high gain high risk so if you are not trying to gambling you wont get much money then always stuck in your life like that, never make any progression at all.
lost massive amounts of money in slots and couldn't even reach break even. I thought of stopping at all but that won't double my coins either
So I started following this simple technique ,everyday for a particular amount only two roles of slots I will spin.