Strength heroes is noted for their Survivability in the Teamfights. Usually, Strength hero is a tanker that should the damages in every teamfight. Tanker hero is the initiator of a teamfight that should come first to the battlefield. Strength hero: the bravest of all. If you want to choose this hero, you should have a brave heart to play them.
Agility heroes is noted for their attack speed. Usually, An agility hero have a role as a carry on the teamfight. Agility hero should farm on early game and wait until he get enough gold to buy some nice items that will boost their ability. They will shine on late game where attack speed is the main criteria of a successful team
Intelligence heroes is noted for their high nuking ability. The nature of nuke is strong on early game and become weak on late game. So if you want to maxing Int hero potential, you should active on early game and use all your nukes to kills the enemy. Intelligence hero is usually become the support role for the team. that's because they don't need many items to become useful for the team, so they don't need many farm. If you prefer Intelligence hero, then be aggressive on early-mid game, and outkills your enemy in that stage of the game.