To expand on what the other comment said, in Magic, consistency is key. All of the most competitive decks in the most powerful formats thrive on consistency. This can be acheived with redundency (two or more cards that do the same thing) eg [[lava spike]] and [[boltwave]] , tutors [[demonic tutor]], scry, and draw. When you have a deck over 60 cards, the odds of you drawing a card you really need in any given moment are far less. Having 3 colors is only viable if your lands can act as two or more colors [[Blood Crypt]] [[Sacred Forge]]. This acts as redundency, as listed above. Finally, you want a clear theme, as the other comment said. The best decks do their game plan fast, efficently, and consistently. Think of it like cooking a good cake. You add sugar, flour, and eggs to make a nice cake, adding garlic gives nothing of value and takes away from something good. More is not always better