reapplying visitor visa for my mom - advice

[nishantkp]

My mom's (age 66) visa got rejected after very short interview.we have applied again and as per immihelp i wrote a new letter giving details of why would she come back. i also mentioned that I am returning by year end. How one can show these documents like my employer letter and other papers etc.
What r the Qs expected when somebody goes second time within a month?
her pervious interview was 3 Qs?

How many kids? - 2
Where they live? son america, daughter -bhopal
where is Bhopal? - MP
where is MP? -did not wait for anwser
are u alone in your home town? yea .. before she could awnser further that her old mom taken care by her.. and she visits my sister etc. VO returned passport

Now I wrote a detailed letter but how can we present the case to show ties as I am only one from my whole family in US rest r all in India including my sis,

[ABC_XYZ]

Hi, Can you please let me know after how many days you are re-applying? I am under similar conditions. I don't know after how many days one should re-apply for visa after getting rejection?