You do not have to be dressed to kill when you go out to lunch. The best thing about lunch dates is that most of would be in our work clothes and that saves us the agony of choosing the right thing to wear on a first date.
A wonderful thing that you could do when going on a fist date is to make it a group activity, preferably a foursome. This takes away the awkwardness of the situation and definitely takes away all those embarrassing moments of silence.
A group has another advantage in that lesser attention will be focused on each other so that there is less stress and as a result both partners would be more relaxed. It is also safer too, since there is safety in numbers.
But the company to be included should be mutually agreeable and not be thrust upon the other person. But take care to avoid any person who you know to be a chatterbox; it takes all the fun away if one person dominates the conversation.
You may drink if you want to, but do not drink too much on your first date. Not only is it in bad taste but when you are drunk, you might blurt out something which you didnt mean to and that might ruin every thing.