Dogs aren't really stubborn. But they often don't clearly know what's wanted. Make it clear by quickly establishing alpha (dominant leader) status. Be willing to exercise the patience and modest, firm force to get the desired behavior. This can be particularly challenging when training a 'come'.
Dogs naturally want to explore the environment. They sniff everything, turn things over, dig and snatch small objects. As with any training session, minimize the distractions by arranging to be as alone and far from other voices as possible. A backyard with a clear area or a large room with few small objects on the floor is best.
Take advantage of spontaneous behavior by observing when the dog is heading toward you and execute a voice-command/hand gesture pair that's unique for this behavior. Try to select a hand-gesture and word that you wouldn't normally use except during training.
Start by facing the dog, putting it in a sit. Execute the 'stay!' command, then back away a step or two. Issue the hand-gesture and voice command. Praise lavishly for the correct behavior, but never reward 'partial' or incorrect ones.
Repeat, stepping further away. If the the dog comes too soon, put it in a sit/stay and try again. If the dog won't come at all, encourage with a treat or favorite toy.
For the slow learners or the, well let's not say stubborn but just reluctant, leash and collar training can be a useful supplement. Put the dog in a sit/stay and back off a few feet reeling out the slack leash. If the dog refuses to come, give a gentle but unmistakable tug while executing the voice command and hand gesture.
For the dog who comes a little to readily, get a long leash or rope and wrap around a tree or post. As the dog lifts off too early, give the leash a tug and execute a 'stay' command. If you don't have a tree handy, try to find a partner to help with the training. The downside to using a partner is the dog will more readily become confused about whom to obey. Focus on a single person is always more efficient.
As with any training, patience and consistency are essential. Dogs don't spontaneously understand the usefulness of 'come' or any other human-induced behavior. Speaking harshly when the dog commits errors or is willful is usually counter-productive. Establish alpha status by firmness of voice, body posture and willingness to wait for compliance. Physical restraint or leading is a less helpful technique.
Most dogs quickly prove themselves eager to please and responsive to praise following the correct behavior. Just make sure they're the ones 'coming', not you. If necessary, prove that you're the stubborn one.