It's essential that you learn how to train your dog to come as part of its basic dog training. Your dog should want to come when called because it is rewarding and satisfying. Most dogs will come when there are no distractions, especially if you are in the kitchen and they think food might be involved. However, you probably want your dog to come to you no matter what. If your dog only listens when offered treats, this doesn't indicate a very good owner-dog bond.
Assess the Situation
When do you call your dog to you? Is it only to come inside when it's out having fun in the yard? Do you call it to go in its crate for the day? When it's off-leash at the dog park and you are calling to put on the leash and leave? Naturally, you want your dog to come to you no matter what, but make sure that most of the time you are calling your dog for something positive, like belly rubs, a hug, food, a game or to go out and have fun. If you primarily call your dog for things that aren't fun, the dog is going to be less than willing.
Do you call your dog to chastise or punish it? Never do this. If you need to chastise your dog, go to it and do so. Avoid using the dog's name during scolding. Use other words - bad dog, shame on you. Remember, unless you catch your dog actually in the act, punishment afterwards does no good.
Tone of Voice
Dogs pay more attention to our tone of voice and body language than the actual words we use. You don't have to squeak or use baby talk, but try to avoid being overly harsh in your tone. Some dogs won't be so bothered, but many dogs, especially ones with submissive temperaments, can become nervous if you are too demanding in your overall tone. Relax your posture, even kneel down and adopt a welcoming stance. Puppies will come to you happily as long as you are not threatening in any way. If you have an adult dog that may have been treated harshly in the past, it will need reassurance that being called means happy and good feelings.
Some Breeds Are More Distractible Than Others
Consider what your dog was originally bred for. Terriers and scenting dogs were bred to follow scents, hunt animals and work independently from their handlers. Jack Russell Terriers and Beagles are often hardwired to put nose to the ground and follow scents, tuning out everything around them. Field-hunting and herding dogs like Labradors and Collies were developed over centuries to work more closely with humans and be more responsive and attentive to their handlers. Give your dog a little latitude if it is doing what it was bred for doing.
Do you get frustrated when calling your dog 100 times, then act exasperated when it finally does come? Try to avoid this. If your dog isn't coming to you despite your yelling its name repeatedly, then stop doing what isn't working. All you are doing is getting mad and teaching the dog that there are no consequences for not coming. If you are getting frustrated, your dog is less likely to come; it knows you are mad and the chances of good and happy things when it gets to you are diminished.
Bear in mind that any exercises which involve giving treats to your dog are best done when the dog is hungry.
If your dog will stay when you walk out of the room, put it in a stay. If not, have another family member hold it. Go hide. Make it challenging. Call your dog, offering plenty of praise and a treat when it finds you.
If your dog is off leash on a walk, hide behind something. Wait for the dog to notice your absence; if it doesn't, call it and let it find you. Plenty of praise and a treat await.
Whether your dog is on leash or off leash on walks, carry treats or a favorite toy. Get the dog's attention periodically and reward for the attention.
If you call your dog and it decides to play "keep away" and run from you, don't play the game. Turn and run the other way while calling. Most dogs will follow you.
Plan on short daily training sessions with your long line, just a few times daily. Think of training as structured play.
Get yourself a long leash, about 20', for outside. Call the dog to you, preferably not when it is busy following a rabbit scent. If it doesn't come, immediately reel the dog in while offering praise. Reward when the dog gets to you. You teaching your dog that it really has no choice in the matter, and that when it finally does get to you, good and happy things happen. Let him go off again, but keep that leash attached.
Finally, always have fun. Dogs are very pragmatic animals. If coming when called is rewarding for them, they'll willingly come. If it's not, they won't. It's really that simple.
So you approached crate training with patience and persistence and it is still not working for you and your dog. Crate training is not for everyone and is definitely not for every dog. This does not mean that you have a "bad dog" or that there is something wrong with your dog.