i take exahust so u can chace down enaamys faster and prevent them from getting into tower range
i also have ignight because it has good kill potental early game and good harass late game

i start with boots and potions because jarvin has slow bace movement and the potions so u can stay in battle longer
then i get vampric scepter so u have a little life steel.
then phantom dancer for the movement speed and crit chance, and the attack speed ant bad eather
then i buy last wisper so u have the armer penatration and a little attack damage
after that i finish blood thirster so u have more life steel and te attack damage.
then i get black cleaver for more armer penatration and attack speed
once u have that get infinity edge for the attack damage and crit damage
if the mach isent over yet i sell last wisper buy another phantom dancer
ind if the game still hasent ended yet sell your boots for a therd phanton dancer

i max out demacian standerd as fast as possibal while still geting the other abillities
then i fiish dragon strike and finaly golden aegis

pros
powerfull dps
very durrabal
can also be built as tank
good jungle
cons
slow
bad early game