Safety first.

安全第一。

Play it safe.

做事要稳妥。

Play it cool.

做事要冷静。

You'd better be careful.

你要小心一点。

You really must try and take more care.

你一定要更当心一点。

You need to pay more attention to it.

你需要更加留心。

Let's lake this one step at a time.

做这事我们要一步一步来。

Leave nothing to chance.

做任何事情都要有把握。

Take no chances with it.

这事儿可不能碰运气。

Be on your guard.

你要提防着点儿。