The actual best way to win in ranked

Get first blood.

It's not about the gold, it's about the huge psychological effect it has on every player on both teams. People are never playing at their full potential in games, concentration might be lacking, they might be on tilt, etc etc. The best way to win games is change the mood in either a positive way on your team or a negative way on the enemy and getting first blood does both.

That single announcement can really dictate the pace for the rest of the game and if taken advantage of can often lead to a relatively easy victory. Of course this doesn't mean you should always play crazy aggressive early to try and kill your opponent, but it's good to be aware of the effect it can have and capitalize on opportunities should they appear.