development – Naming standards for our SharePoint columns Internal names

I am working on a new SharePoint site, and we want to create many site columns, so can i know what are the naming standards for site columns’ Internal Names inside SharePoint, for example i have those display names:-

  1. Car Number
  2. Registration Name
  3. Date Covered By Customer

so what the internal names for those site columns need to be? if we take the 3rd column as an example should it be defined as DateCoveredByCustomer OR Datecoveredbycustomer OR datecoveredbycustomer or another option?? as based on my test internal names for SharePoint sites column are case sensitive.. any advice?
thanks