if you are not getting any kills in the first 10 minutes and you are getting zoned and can't cs, buy 2 doran's blades.

if you are getting a lot of kills in the first 10, rush the infinity edge and go strait into phantom dancer because you wont need the sustain of the vampiric scepter as much as much.

if there is no really strong amour tanks like rammus, malphite or even someone like renekton or wu kong with an amour heavy build, dont bother with black cleaver and last wisper and get a second blood thirster and a seconds phantom dancer.

in lane miss fortune has very good synergy with agressive supports like leona and taric, if you combo taric's dazzle with miss fortunes Double up and auto attacks, it is very easy to harass because of the burst damage provided by double up combine with an auto attack. zoning is also easy with miss fortune because using the burst from your double up and auto attack combo you can easily win damage trades and make the enemy ADC think you are too strong for them.

in team fights try to focus the enemy AD and AP carries, if focusing these targets will put you out of position, try to take down the next most squishy target.

do not ulti unless you know you can hit at least 3 enemies with the full channel. if you can not you will do better DPS with auto attacks.