format the codes produced so they are easier to compare

[Beliavsky]

Use :: in all declarations for example. Maybe use an auto-formatting tool for Fortran code.

[Beliavsky]

You can specify the name of the variable in which the result is to be stored and suggest that loop variables be named i, j, k etc. In a main program you can move assignments to variables (as opposed to named constants) from declarations to code after declarations. So

integer :: i=1

becomes

integer :: i
i = 1

[Beliavsky]

In style instructions you can specify that one-line-if statements

if (tf) statement

are preferred over

if (tf) then
   statement
end if

when possible.