Lee has been my main for quite a while so I decided to share my experience with him.

For runes : yellow - 9 x flat armor , red - 8 x flat AD + 1 x critical chance ~ 1 % , blue - 9 x scaling magic resist, quints 1 Move-speed + 2 flat AD.

Why ?
1 MS quint makes U as fast as the 2 fastest champions in the league- Yi and Pantheon. Your base MS is 350, theirs 355 with this quint you become unchasable, the one who does what he pleases.

1 crit red for the fool's hope

I have tested many masteries on lee sin yet I prefer 9 / 21 / 0

2 point in Safeguard early for Health regain in jungle. While others lose health jungling, you gain more that you lose if you proc smite, tempest and sonic wave while Iron will is up.

Smite on your Iron will when ganking and receiving damage, it might save your ***. When you walk away from the battlefield seeing enemies crying in all chat : "Lucker, he has 30 hp!" Just smile they wouldn't understand anyway. Do the same with your tempest on minion wave if you fell like extra HP is needed.

And of course ward jump. Always carry wards with you even if you don't know how to do the jump by the time everyone gets used to it plus extra vision is never bad.