Secretive
We know that on a first date, most singles don't expose their deepest darkest secrets, but keep an eye out for someone who refuses to answer any questions.
Work related questions, unless the job is completely confidential like CIA, FBI, or some military service, there is no reason for him/her to hide it from you. Ask yourself if they are avoiding questions or just uncomfortable talking about it. The difference is that someone who has family issues will not avoid the question and actually tell you he doesn't want to talk about it.
Overly Sexual
Some singles are open to the whole just sex thing but if you aren't listen to how often the topic comes up. Make sure that innuendos are just jokes and not subliminal messages. If he/she is all over you physically, that is a bright light as to what they are looking for.
Money Issues
I know you have heard those stories about people who started dating someone and in a couple of months they ran away with their
life savings. Just like sex, see how often the topic of money comes up. Is your date either boasting about major investments s/he made, or telling you about their poor helpless mother. If they talk a lot about money, they are all about money.
Day Dreamer
How often have you found your dating partner day dreaming or caught them not listening as they answer questions inappropriately. Don't be fooled, this is a person with A.D.D. which you may not want, or have the capability to focus for too long. Do you really want someone like that?
Wondering Eye
Not all singles that look necessarily touch and just because they don't look it doesn't mean that they are faithful. However, statistically you are more likely to get cheated on by a wo/man who can't keep their eyes on their plate. Focus to see if you are sitting in front of one of those people.
Control Freaks
Who decided your date? Who ordered your food? Who did most of the talking? It is easy to let this one slide, but if he controlled what, when, where and why, he might have a slight control problem. The best way to
test it is to attempt to make a suggestion and see how much attention is actually paid to it or if any offence is take by it. If there is an issue, you may have yourself a control freak.