WARNING, CAUTION The following expressions can be used to warn somebody:
Look out! Mind…! Hold tight! – to passengers (in a bus, etc)
Don’t rush, take it easy! – a policeman to a crowd.
Mind you…Make sure you… (+ inf. without ‘to’) Mind you don’t… Take care you don’t… Take care not to… Mind how you… Be careful (with…) Steady on (with…)! – informal
Though in form of a caution, these expressions imply a definite threat:
You are asking for trouble! Watch your step! I should watch my step, if I were you.
A warning may take the form of threat:
If you… I/we shall… If you… I/we shan’t… You’d better (not). Stop (doing) that, or else I… You’ll be sorry, if/when…– often mixed with anger
Colloquial:
You are for it! You’ve done it now! You’ll catch it!