So many contacts, so little time. That’s the dilemma many professionals face when seeking referrals. To make the best use of your time, you need to prioritize your contact strategy.

But after you reach out to your top clients, whom should you target? What qualities should you look for when selecting good sources for referrals? And how can you tackle this along with everything else you have to do?

Fortunately, there are some characteristics that can help you identify a good referral source in just five minutes or less.

1. A large network

It goes without saying that someone with many professional connections has a greater likelihood of referring business to you, and it’s fairly easy to get an idea of the size of your contact’s professional network.

A simple search on LinkedIn and Twitter will lead you to an individual’s profile which displays the total number of his or her connections and followers. While your contact may not have a close relationship with the majority of these people, a high number of connections is a good indicator that this person values professional networking.

2. Active engagement

Of course, being connected to a lot of people is useless without interaction. With a little online research, you’ll be able to easily tell if a professional is interacting and making a good impression within his or her own network. Do a quick scan of this social media activity to get a sense of how the professional is sharing, commenting on other people’s updates, and engaging in conversations

If your budget allows, you might use a social analytics tool such as BuzzSumo. Simply open the interface and then type in a name; under the ‘Influencers’ tab, you will see statistics for ‘reply ratio’ and ‘retweet ratio’. Both are good indicators that the person is interacting within his or her own network, and not just broadcasting their own messages.

3. A genuine interest in others

The most effective referrals come from one person’s desire to help another. These people are the ones who are more likely to refer you—even without being prompted—if they know of someone in need of your services.

During a conversation, you can tell pretty quickly whether a contact shows an interest in others. They will ask questions. They will pay attention to the responses, and they will talk more about others than they will about themselves.

4. Good listening skills

By listening to what others say, good contacts can identify potential referral opportunities. For instance, a friend won’t always ask your contact if they know of a good real estate agent; but if the contact mentions that they are expecting another child, an observant listener might recognize the potential need for a bigger house.

If someone is a good listener, it’s another trait that will be apparent when you talk with them for a few minutes. If they are more interested in what they have to say than what you have to say, however, they probably won’t be able to pick up on any referral opportunities.

5. Enthusiasm about your service

Your biggest fans are often your best referral sources—not because they know more people, but because they come across as more convincing to the people they do know. You can’t fake enthusiasm; it’s contagious. These influencers are also the most likely to go out of their way to sing your praises. You can count on them for unsolicited referrals.

You shouldn’t even have to start a conversation in order to know who these people are. You’ll know, because they keep coming back to you—and because they go out of their way to post positive reviews about you.

Once you know who your best referral sources are, make sure you build a relationship with them. Keep in regular contact with them, and don’t forget to actually ask them for referrals.