Usually, focus will be very narrow – often to the exclusion of all but the hypnotist’s voice – so if you don’t think you’re hypnotized (just very relaxed), but then find you’re not doing much except what the hypnotist tells you, then it’s safe to assume that you are hypnotized. Similarly, when instructed to do something whilst in hypnosis, it’s generally the case that you’ll do it automatically without any deliberate effort on your part – it just seems to “happen”. This tendency to automatic response is another good indicator that hypnotization has indeed happened.
Many people, especially during their first hypnosis experiences, do not think they’ve been hypnotized because they expect their minds to be blank. It is, however, rare for such to occur – hypnotic amnesia is uncommon, except in the minority of people (about 10%) who can readily enter a somnambulistic state. Generally, however, if you followed the hypnotist’s instructions; entered a very relaxed state, and only really did anything when it was suggested to you, then it’s probable that you were hypnotized.