Having recently had to ask 500 people (in various age and gender categories) about taxi services in their council area, I can tell you that it's not a case of looking for people who'll answer your questions. It's simply a matter of avoiding those who won't!
For example, I wouldn't waste my time trying to ask anyone who is:
(a) having a row with their partner ;
(b) shouting at their kids ;
(c) deep in conversation with their companion ;
(d) making a mobile phone call ;
(e) staggering with a load of shopping ;
(f) clearly trying to avoid eye contact with me ;
(g) obviously in a hurry ;
(h) drinking from a can of extra strength lager ;
(i) clearly too young for me to speak to without 'arousing suspicions' ;
(j) clearly too old to stand still in the cold without collapsing ;
(k) conversing with someone else in a foreign language. (Yes, I know that they might speak perfect English but why take the risk of having to struggle with sign language?) ;
(l) acting in any way that silently shouts "Beware of the loony!"
So, if you're on your own, neither very young nor very old, not drunk, mad, foreign, burdened with shopping, in a hurry or on the phone, there's a very good chance that I might want to speak to you. So, please, please, please, don't avoid eye contact with me! ;-)
Chris