Informative talks to smaller groups allow you more intimacy with the audience. You will be able to more closely connect with their needs and their responses to your speech. You have something to say that is important not only to you but to the audience as well. They will take time to listen and not socialize as long as what you have to say is relevant to their pursuits. If you are not relevant, you must find a way to make your topic something they want to know. You must make them aware of the importance of your topic. Suggest books they can read, suggest ways they can use the content of your speech to their advantage to make improvements at work or at home. You want to make sure that you deliver something of value
The point of an informative speech is not to sell yourself and make it an infomercial. The point is to inform the audience of a salient topic and give them information that they can use immediately. Once you have accomplished that task, gaining additional bookings will be easy. I have sat in many audiences and really enjoyed the speeches except when it came to the end and they went into full commercial mode. A successful speaker that is making an informative speech does not do it; they simply let the audience know they will be available for questions at the end of the speech.
An informative talk should also have some supporting materials so that it is easier for the audience to follow along. Many speakers do not want to take the time or spend the money to provide unbiased hand-outs. The one thing I do is make sure they have a worksheet where they can jot down important information (which they keep for future reference). Be ready to dole out free information.