I played chess for more than 10 years. I am not the all-time champion, nor the greatest Chess player, but I have experienced playing different kind of Chess plays.
I played Chess on Internet for 3 years but stopped almost 2 years until I came back playing yesterday. When I played a game yesterday, I almost forgot how to close an end game, checkmating an opponent. I almost blew that game away. But a player noticed the way I play the game, he said that I am a great player, but I'm denying it many times, but he forces his opinion. He asks me to teach some points in making plays in Chess. I didnt answer him. But as a player id like to share some points. Now heres the answer.
If you play a fast game, a bullet or a blitz, its not neccesary to checkmate your opponent, because the is short and hey, your opponent can play chess as you do. Playing fast is playing time. You must see to it that you move quickly but precisely. A defensive play is a good style. How to do it? Memorize atleast 25 moves that you can make sure that you will not be checkmated. Its enough time to melt your opponents time, 2-5 minutes.
For a standard play, time is also needed but knowledge of the game does wins game. Its up to you whether you play offense or deffense but the best play to do is being cautious to your opponent and to the time.
Hope it helps.