An important part of teaching recall is to make training a game for your dog. You want your dog to think that coming and being near you is the best thing imaginable, full of fantastic treats and rewards.
Start your training in a slow, low-distraction environment, like inside your house. First, show your dog a toy or a treat, praise them as they are coming to you, then reward them. After a few repetitions, whenever your dog looks at you and starts to move towards you, add in your chosen verbal cue (come, here, etc.). Make sure to only add in the cue when you are confident your dog is moving towards you.
You can slowly up the ante by asking your dog to come before showing them the treat. But, be sure to reward with a high-value treat like chicken, cheese, or beef liver, when they get to you. Also, try slowly adding distance within your low-distraction environment.
A common training mistake is to recall the dog, put the leash on, and go home. Dogs will likely learn to view recall as a sign that the fun is over. Understandably, this may make them less likely to come in the future. One good method of practice is to recall, praise, and treat, then release your dog to return to whatever fun thing they were doing before.