The thing with this build is to make Miss Fortune do what she does best.. ALOT of damage!
She'll be weak for attacks by the enemy, and should never go alone without some sort of tank/support and always try to stay behind friendlies.

With her strut she'll reach combat fast, and if she gets attacked her enchanted boots will make her able to hit the enemy and move away with the short move-boost. Keep making small stops to harass the assaulting enemy, damaging him and at the same time keeping your movement-boost up and running.

I guess Flash would help her (you) in tricky spots, but with ghost you'll have a much better chance to reach a fight where you are needed in time or to outrun an enemy chasing you. It's my impression that everyone has flash today so you'll get killed no matter on what side of a tree you're flashing if the enemy flashes after you.

The Eleisa's Miracle is probably nothing you really need to buy, but if you get to farm well on your own you could get enough money real quick to spend it on this beauty. I hope in the end it will benefit you with its small health and mana-regen.