Super Smash Bros. is a lot like being a serial killer. You have to know what you're doing. Know your character, know the technical aspects of the game, stuff like that. You also have to know your victims. Get a good hold of what they're doing. Their patterns, reaction, and how they play. Remember: If you have the opportunity to kill, take it. Additionally, you need to throw off the pattern if you don't want to be caught (punished). Like to cover rolls with a downsmash? Throw in a dash grab from time to time. Always recover high? Ride low for a bit. Finally, but most importantly, take advice from one of the best Smash Bros. players of all time. Don't get hit.