Unfortunately, newcomers are often slow to find partners and, therefore, tend to congregate far from the orchestra. Experienced dancers can help by using some forethought and making themselves available early. Don't wait for a beginner to approach you. Take the initiative and position your partner where they are not surrounded by other beginners. This means more fun for them and for you.
Experienced dancers can help by explaining the basic figures.
By far, this is the most common mistake. Verbal explanations are often more confusing than helpful and can increase anxiety by giving too much information. Almost all of what is dealt with in these efforts at explaining will be learned during the walk-through with far less effort. In fact, by offering instruction in the dance line you will be teaching beginners to look to you for guidance rather than the caller. Your most useful role is to help your partner relax and build their self-confidence.