Monkey king is extremely dangerous opponent as skillset provides him quite versatile, powerful abilities, but being heavily limited with mana he's forced to use wise even a single one early game. Incredible mobility and huge damage output are more than suitable for choosing aggressive playstyle on the other hand.
Stay back taking safe lasthits until you level up all your abilities and purchase a Bottle. Nuke enemy down with Vault-Slam-Vault combo (knocking opponent back with second Vault right on the mound, raised by Slam) and lay a killing blow with Dash-Attack-Dash or use it to shorten distance instantly when victim is already wounded. Roam across the map, looking for weak heroes to gain momentum.
Aim for Bulwark to boost your burst combo potential with negative armor aura and start building survivability to dominate mid game and win every skirmish. Shieldbreaker is great pickup when combos become less effective and you need Dash to fully shine as main source of damage later on.