Table Headers
Tables can be very tricky for assistive technology (like a screen reader) to understand, especially if there are many rows and columns. This is solved by using table headers, which indicate the header for the row and column of a table. You can see some examples of tables with headers at Penn State University's accessibility site.
Doing it in Cascade
If your table is more complicated than a basic table with headers on the top and/or left, you should probably ask for help in getting it formatted.
How to verify
The simplest way to verify is to browse your site on staging with a browser that has the WAVE Toolbar installed. Running the "Errors, Features, and Alerts" report will show you where problems exist.
If you cannot install the WAVE Toolbar in your browser, try using the WAVE online web accessibility checker tool instead.