We outline two builds above for Li Li. Li Li may not be so popular at the moment, but there's some clever stuff you can do with her.

"You Don't Get to Auto Attack"

This is mostly a troll build but can be used for some fun applications. The point of this build is to make Blinding Wind hit as many targets as possible and inflict as much missed auto attacks as you can. With this build you can use your Blinding Wind a huge range away to hit up to 5 targets and make them miss 2 auto attacks apiece. This constitutes a huge amount of damage lost for their team. Follow this up with Jug of 1,000 cups and it's level 20 buff for some reasonable heals with this.

"Sustain/Heals"

Ok, this one is a more serious build. Concentrate on extra heals (hence the Healing Ward pick at level 4) and damage mitigation (Shrink Ray at level 13). The point of Li Li in this meta is to sustain in lane to a ridiculous degree. Pick a solo lane matchup against a hero without much sustain and constantly spam your Q and W. You'll do great damage but also stay near top health the entire time.

As you move into the midgame, your number one priority in fights (apart from the obvious heals) is to drop your W on ranged assassins. Your serpent will add a ton of damage to their autoattacks, and since you're talenting the serpent at level 7 to give health and mana, your ranged assassin will like the additional heals anyway.

Late game you don't scale especially well. Take the Jug of 1,000,000 Cups talent at level 20 to effectively double the healing of your ultimate, but otherwise concentrate on spamming that Q and W.