Report standards will have two levels: a technical level and a presentation level.
On a technical level it relates to following suggested best practices:
Examples: Having variables identified with v_xxxx, deleting all unused variables, ensuring that your report is optimal in the objects that you have selected and where you apply aggregation, providing prompts to help reduce data fetches, proper use of contexts etc
I.e. if you have to pull a million rows to sum some data on a report, rather request a new object to sum the data on the database before sending it to the report …
Look around for some presentations and read the vendor guides:
Here’s a good place to start http://www.integrasolutions.net/library_presentations.htm#reporting
On a presentation level you need to adopt a corporate standard as to how you define your reports - typically by using a template to make sure your Logo, colours, date & time, page numbering etc are all consistant across all reports.
Then you should be able to develop by own by considering the below key factors
Table positions
Titles
Header
Footer
Page NO
Table start position
Colum Heading
Row Heading
Formating of Numerical, Date and character values
Positions between two tables
Page Margins