Visitor Visa - B2

I am planning to apply for US visa this coming October but i'm bit hesitant to do it because I heard a lot of horror stories in getting US Visa. Hope you guys can help me and hear your opinion on how to over come the interview.

Here is my profile.
-I am 26 Yrs old from the Philippines.
-Employed Full time
-Working in BPO
-Single
-I don't have any property but I have small savings accounts which I think I can afford to go to US for 2 weeks.
-All of my family are here in the Philippines
-I have distant relatives in Florida (Cousins of my mom) but they were like sister because they grow up together) she asked me to come to FL so she could take me to Disney World.
-Shes already American Citizen.
-She is just a plain housewife, but her husband is Policeman in FL.
-I have been to Japan 3 Times already (Handling Multiple entry visa for 5 Years) Taiwan 2 times, Hong Kong, Singapore, Malaysia and South Korea and recently i got approved for 1 Year multiple entry for Australian Visa(This is business visa processed by the company i'm working) i haven't been to AU hopefully this August.
 
Questions..
What are the possible questions that might ask?
Would it be ok if I will ask for invitation letter from my Aunt even if she's not working?
What are my chances in getting approved based on my Profile?

Hope to hear from you guys. Thank you