Wukong is an excellent solo lane champion, with a combination of burst damage, durability and difficulty to gank. His basic harass method is closing the gap with [E] Nimbus Strike, autoattacking with an immediate [Q] Crushing Blow afterwards, and then using Decoy to avoid retaliation. Leading with [Q] Crushing Blow will reduce the opponent's armor, increasing your damage output. [Q] Crushing Blow ignores the attack cycle, using it immediately after an autoattack will give you a 'free' attack. Both [E] Nimbus Strike and [R] Cyclone allow Wukong to close the gap between him and his target. Using [W] Decoy is an effective way of escaping and chasing down enemy champions. By pressing "stop" [default key: S] you can pretend that you have used [W] Decoy to make your opponents think that you are the decoy. However, this move may not work on skilled opponents. This is less effective against more skilled opponents, because the [W] decoy doesn't show any visual effects ( Blessing of the Lizard Elder/ Crest of the Ancient Golem buff, Oracle's Elixir, Poison, Mordekaiser's Children of the Grave, etc). This means it is usually easy to tell if Wukong has really used a [W] decoy or not.
When ganking an enemy from the brush, use [W] Decoy while inside and approach your target during the stealth time. When fleeing, consider how best to utilize the brief stealth provided by [W] Decoy. Use it to juke your pursuers by changing directions after using [W] Decoy. Sometimes it's best to simply stop after casting [W] Decoy and watch as your opponents continue to chase in the direction they think you've gone, this is known as 'stop juking.'
[W] Decoy can be used as a shield against skillshots or even Caitlyn's Ace in the Hole. [W] Decoy always appears behind you. It can also be used to stop Rammus's Powerball. If [W] Decoy is used exactly when Karthus's [R] Requiemhits, the damage will be nullified or taken by the decoy. [Q] Crushing Blow's bonus damage works on turrets and inhibitors.
[R] Cyclone is not a channeled ability so crowd control effects, like stun, silence or knockback will not cancel or interrupt his ultimate. However stuns or snares will prevent him from moving. General team fighting with Wukong should aim to persist in the fight as long as possible utilizing his skills multiple times while also disrupting the enemy team and not getting focused down. Such an approach is to use [E] Nimbus Strike to close on a dangerous enemy, autoattack, use [Q] Crushing Blow for another attack, and then immediately use [W] Decoy since enemy crowd control and burst may be headed your way. While stealthed, you can back off and reposition yourself. Then re-enter the fray with another Nimbus Strike and another [Q] Crushing Blow before activating [R] Cyclone to disrupt their team as they come after you knowing you don't have [W] Decoy available. After [R] Cyclone finishes, you should be close to having [E] Nimbus Strike ready again to chase down an enemy or smartly target to aid your escape. Try to hang onto your [R] Cyclone during teamfights instead of using it to initiate fights, your visibility with your ultimate and high damage output will put focus onto you from the enemy team. Instead use it as a strong crowd control to break up enemy champions and to chase.