Tapping the jump button instead of holding it down allows Clunk to remain in air longer as well as reach places that would otherwise be too high.
When playing as Clunk, you will most likely want boots to improve his slow movement speed.
Using Vacuum Bite on a neutral creep will not only give you the normal lifesteal, but the healthpack it drops as well for a more powerful heal.
When using Multi Hose, try to save Vacuum Bite for two targets as often as possible, as you will get twice as much lifesteal. Just remember it doesn't affect the same target twice.
It is possible to kill yourself with Self-Destruct! Think twice before activating it.
Biting two targets at once with Multi Hose will not cause two healing over time effects from Power Converter to take place, however, biting two targets with two separate bites will.
A popular tactic among Clunk players involves charging up Self-Destruct and dropping from a high place on top of unsuspecting enemies, giving them less time to escape the blast radius.
Self-Destruct can be used to save an ally from danger. Simply activate it and block their pursuers' path. Most of them will give up chase or take severe damage, maybe even allowing you to finish them off. It can also be used to discourage enemies that would otherwise attack you if you feel you can't take them down.
When using either Missile Barrage, The Juggernaut "Fat Pete" or Salvo Value Pack, it is possible to keep track of your launch string. That way, you can store a more powerful missle just before a teamfight. These upgrades also stack, meaning Clunk can fire two missiles at once.
Playing Against:
The absolutely best moment to attack an enemy Clunk is when both Self-Destruct and Vacuum Bite are on cooldown, specially if he misses the bite trying to get extra health.
Aside from missles, Clunk's abilities have relatively short range. Try to keep him a safe distance from you.
Being a very slow and big awesomenaut, Clunk is naturally vulnerable to poking. Try to attack him from a safe distance, specially when he approaches Droids for a healing bite. That way he can end up taking more damage than he can heal and may be forced to retreat.