This is the sentence that reveals the most to me about you: "基本上,我都觉得这么帖子不靠谱,又不是别人说了你能进去你就能进去。不过,大概人都需要从别人那里获得一点assurance吧。"
If you can display a similar level of self-awareness and self-honesty in your essays, you should be fine. All the other stuff you mentioned is really not very revealing (GMAT, etc), because these things are 1) not very important 2) do not differ much from applicant to applicant.
GMAT of 730 may or may not be fine- depending on your breakdown between math and verbal, your GPA, evidence of your English ability through the essays, interviews, and so on.