What is a proper convention for a date?

If you mean the structure for a date, then there are two general formats, which are having the date in day, month, year order or having it in month, day, year order. This can be confusing for dates up to the 12th of the month. To avoid confusion it is often a good idea to write a month in Words and show 4 digits for a date. If you take a date like 2/3/50, that could be the 2nd of March 1950 or February 3rd 1950, depending on which date format you normally use. Using the Word for the month makes it clear, whichever format you normally use. There are also different ways of showing the year, with either two digits or four digits. Again writing a long form of a date avoids confusion.