Playing fetch can work. However, the drawback is that the dog may not come if you are not playing fetch.
Get a 20' or 30' training lead and start by using the dogs name then 'COME' or kommst, or whatever command you wish to use.
Don't pat on your thighs, don't bend over, and don't beg the dog.
Give a little tug on the lead and repeat the command. You can use a clicker and treats as I did while teaching this or do it without. Keep repeating this and they will soon understand what you want.
If a dog learns nothing else its entire life, this is one command it must know. It could save the dogs life one day.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf