PL is an agility hard carry that with a lot of farm can completely dominate a game but can be rendered much less effective if the oposing team has lots of AoE abilitys
This is you bread and butter in lane spell its your nuke harass and slow all in one but it is very expensive early game to spam without mana boots or aquila.
This is your two in one escape ability it gives not only invisability but also increases your movement speed while it is active
This is the ability the makes PL what he is making him difficult to focus down in teamfights without a gem. (Note: I prefer to skip this skill early in the game because it will push the lane and reduce your farm)
This ability boosts you in general the magic resistance will help you survive AoE abilities and nukes the increases juxtapose chance will help you spawn illusions faster and more often and this gives your illusions a chance to spawn their own illusions.
Get the salve and tangos as normal lane regen and the stout shield because you will most likely be harass a lot in lane
Get the ring of quila to help you spam out your spirit lance in lane be sure to turn it off or the lane will push out. Power treads are the best stat on PL because the changing of the stats can help you use your spirit lance more and switch to strength in emergencies to stay alive.
Vanguard is good to make you very survivable and difficult to kill. Radiance will help you farm a lot faster because your illusions will also have the radience burn effect.
Diffusal is a good pick up on PL because your illusions will get the mana burn aspect of the item giving you AM level mana burn. For later in the game you could replace your vanguard with a heart to give you more hp and survivability. MKB can be gotten if you are against someone with evasion or you just want to hit harder. BKB is good if the other team has AoE stuns and you are being locked down. Butterfly can be gotten if you want to do more damage and get some evasion.
You can use PL's illusions to jungle at multiple camps at once allowing you to farm at amazing levels once you get your radience and being able to kill ancients at a pretty low level. You must remember to move your illusions out of the camps though once they are dead or you mught block the spawns so you decrease your farm rate.
PL needs a team that can play 4v5 dota for a while so he can farm up in the early to mid game with his team also needing to protect him PL should only realy join the fights early if the tier threes are being threatend.