Queen + King vs. King checkmate is the easiest checkmate in the endgame. But I have observed that many beginners end up making a stalemate. In order to avoid that I’ve been teaching my kids a way that I think works well. Kids easily remember steps. If you have a difficult topic then divide it into steps.
This method is for beginners. I call this the ‘long way’. The objective is to push the opponent’s king to one of the edges of the board. Make sure that you don't stalemate him in the process of pushing his King. Once he is restricted to one of the edges then get your King closer so as to get an opposition. After that you can give check with your Queen (as shown in the video) to checkmate your opponent.
The above mentioned method is a little slow for advanced level players. A Queen+ King vs. King checkmate should not take more than 8 moves. Wherever the opponent’s King is – with this method – it does not matter. We can checkmate within 8 moves. The logic behind this method is that we are pushing our opponent's King to the edge as well as towards our King. So that our King doesn't have to make a long trip around the boards. Follow this method carefully. There are chances that you may stalemate your opponent.
If you have a better way to checkmate then please let me know. Comment if you have any doubts.