1) She "swims against the tide" is the opposite of "living an ordinary life."
2) Since she is LIVING an ordinary life, she should be PAYING no attention
- this matching of verb forms (the "ing" form in this case) is called "parallelism," and it is a grammar fault to fail to make the verbs parallel
3) the expression is "pay no attention TO" (not ON)
4) "THE cumulative" effectS I think, not "accumulated effect"
5) Probably "effect ON" should be "effect OF"
5) It is impossible to tell what sentence means toward the end -- it's that "like others" that messes the meaning up
"She swims against the tide by living an ordinary life and paying no attention to the cumulative effects of a large sum of money like others."
Possibly it means "UNLIKE others, she lives an ordinary life, paying no attention to the cumulative effects of a large sum of money."