Hi 

I think the below are the two components to getting paid on time

1.Automating the task of sending email reminders.well timed email reminders are known to improve DSO's

2. The content that goes into those mails needs to be thought through

I would suggest writing on a board the timeline before and after the invoice due date in days

---10 ------5-----3----1-------0--------(-3)----------(-10)----------------------(-20)--------------------------

After this come up with mail content for each of these dates.Make sure these automated emails have one of you/your team members in cc so that they can reply back to you to have any questions cleared.

Btw we are a small software(PayorCRM) company automating the above function

Regards

Megan