Lee Sin can burst by using his abilities and their secondary activations in rapid succession but that quickly depletes his energy.
李青的Flurry adds 40% attack speed to the two basic attacks that immediately follow, each of which also refund 15 energy. In order to maximize this buff's effects, stagger (space out) your abilities with autoattacks in between.
One of the most effective methods of harassing with Lee Sin is to use Resonating StrikeResonating Strike to attack an enemy and then immediately retreat with Safeguard. This can be a powerful move early on in the laning phase. You can begin using this combo as early as Level 2 and often the opposing champion(s) have limited means of retaliation.
On the top lane, if you face a Champion who mainly use AOE spells to harras (e.g darius Decimate), You can force him to push the minion wave without getting hit by using the method mentioned above and then make an easy gank with your jungler.
You can add Dragon's Rage to the combo if you otherwise lack the damage to finish the target off.
Smartcasting Safeguard might be just enough to give you the edge you need, when using this strategy, to dash in and out with a kill.
Safeguard has a primary defensive use but it can be effective in an offensive context as well. If an enemy champion is out of range of Sonic Wave, but is in melee range of an allied minion or champion, use Safeguard to jump right in.
Safeguard is essential to have "leveled up" when you're facing off against a bruiser.
Safeguard cannot be cast while snared, even if Lee Sin targets himself, as it classified as a dash/movement ability.
Tempest and Sonic Wave is a great combo for fighting champions with stealth or those trying to juke or hide in brush. Combining both skill can keep an enemy revealed for up to 7 seconds and at higher ranks or with CDR it's enough to have the combo ready again.
Using Dragon's Rage can disrupt the enemy team's positioning at the beginning of a teamfight . Not only will Dragon's Rage knock an enemy back (preferably the tank or bruiser), but it will also knock up the champions hiding behind him.
Dragon's Rage can also be used to interrupt a channeling ability if your team has their interrupts on cooldown.
Be careful about using Dragon's Rage as a finisher, as one incorrect calculation may lead to the target escaping instead.
You have to make sure to aim Dragon's Rage correctly as this can prove to be crucial mistake in team fights. For example: kicking an enemy champion out of range of a friendly 阿木木的Curse of the Sad Mummy.
Lee Sin requires a fair amount of survivability due to how close he must get to enemies while he fights and the time it takes for him to utilize his passive, getting items like Wriggle's Lantern and Hexdrinker early can have noticeable results. Building Lee Sin tanky is important because to use his ult properly he needs to be able to survive being in the middle of the fight.
Trinity Force will also provide some ability power to slightly improve the shield from Safeguard without sacrificing an item spot purely on AP, in addition to its plethora of beneficial effects and stats.
Since Lee Sin does not use mana and scales well with attack damage, it can often be better to build the much cheaper Hexdrinker rather than the more expensive but more popular Banshee's Veil (which Lee Sin wouldn't be able to use the mana portion of anyway).
When playing jungle Lee Sin, you can use Wriggle's Lantern to place free wards for not only vision and map control, but also for synergy with Safeguard. This allows you to hop over walls to gank/escape enemies.
Cripple will only slow you if he hits you with Tempest. Make sure you stay away from the ability's AoE in order to avoid the slow.
Beware when committing to kill Lee Sin. With wards in his inventory to place and cast Safeguard on, jungle monsters or enemy minions to hit with Sonic Wave and Resonating StrikeResonating Strike to, and having Dragon's Rage available to knockback enemies a large distance or knock them up into the air, Lee Sin has an enormous amount of potential to escape and evade dogged enemies, causing said enemies to waste a large amount of time chasing him at best.
Instead of battling him in minion wave, try to fight him when he is alone so he can't make the full use of the dash from his Safeguard.