Whenever you are looking for the right couples to swing with there are a few things to keep in mind. You will find that it is usually a good idea to go out with the couple first, even just for drinks or lunch so that you and your partner can make a good decision about whether or not this couple will be worth your time or if you should continue looking. However when you find the couple that you want to swing with you may find it better to sit and talk with them briefly.
It is usually a good idea for you to try to see if you have any type of spark or connection with the person that you are thinking about swapping with. You will find that swinging with another couple is something that is going to require more than just the working parts. Have a drink with them and see if you and your partner are able to connect with this couple on some level. If only one of you does, then you may want to consider not swinging with them at all as this can end up being something that is unpleasant for one or two of you.
Of course it is really important for you to be attracted to these people on some level. Being attracted to a couple that you swing with is imperative as you will be able to enjoy the sex a lot more. If you are not drawn to them right away, then look for parts of them that can turn you on.