Genealogists generally write dates in this fashion: 16 Jul 2015. This separates the day of the month from the year, and using the four-digit year eliminates confusion as to which century you mean. Each month is (usually) abbreviated to the first three letters.
If you are working in a genealogy program or online tree, you might not have to abbreviate the months. It does help when filling out forms by hand, though.
Part of the reason for using this format is because that is how dates are written in Europe. So using this format lets you get used to how the dates are used there (helpful when you are looking at records from Europe). It also avoids confusion that is possible if you write a date in just numbers, as 11/01/01. Is that November 1, 2001 (or 1901 or 1801), or January 11 in some year that ends in 01? Looking at 11 Jan 2001, it’s easy to tell the correct date.