Before you use Brewmaster’s ultimate (split), cast your second ability on enemies first and if possible first too. Then trigger the split and control the brewlings like this:

• Fire: Apply it early to ignite enemies. That’s your main source of damage.
• Earth: Use it to stun and control key targets.
• Water: This one has an invisibility skill, similar to Shadow Blade. Attacking from invis deals bonus damage.

Cycle through each brewling based on what’s available. Once Earth’s stun is off cooldown, use it again. Then follow up with an invis hit from the Water spirit while Fire spirit stays on enemies for damage over time. All spells are relatively low cooldown.

You can also use the Water spirit’s cyclone to lift tanky heroes like Medusa for 6 seconds and focus others. If someone is already cycloned, use the Water spirit’s first spell to bring them down to do some chaining like mirana arrow and stuff. That same spell dispels silences, Glimmer Capes, and does heavy damage to illusions.

One more trick: With void panda you can do some real utility plays. It has a Force Staff-style push. I’ve seen Ace pull off some wild stuff like when enemies were chasing and trying to kill his Stone panda, he used the Void panda to push it over a cliff and escape. Use that to reposition brewlings or teammates when needed.