how do you know if your ramdan has been accepted?

you cannot, but what you can know is if you've performed well or not, if you think you have performed well you just hope Allah accepts your efforts

In Army they taught:
Your is not toquestion WHY.
Your is just do or die.

I personally believe in action no matter how big or small. Just it should be coupled woth best intentions and you put your heart and soul in it. Leave rest on Allah SWT who does not waste someone's deeds.

May Allah SWT accept from you and us all, Inshallah