[alaskayorkie]

Try to make "come" the funnest thing your dog does in life. I took my guy to the park and had a neighbor kid hold him. I walked several paces away and shouted COME in my most animated voice as the neighbor released him. He raced to me, and I rewarded with praise, praise, praise and several tiny treats. I'd do that for 10-15 minutes a day, gradually increasing the distance. Eventually, you can hide from your pup and they'll find you.

In obedience, they teach sit-stays. Once you get them in a sit-stay, it doesn't matter how far you walk away from them. The secret is gradually increasing the TIME before you allow them to break and come to you. If your dog won't sit-stay, put one foot on the leash so they can't move. Tell them to stay. After a while, let your foot off the leash and say COME. Always reward with praise and treats.
Good luck!