Go by your initials. Use your first two initials (or both initials if you don't have a middle name) to make a nickname. For example, someone named "Thomas James" could be "TJ" or someone named "Mary Katharine" could go by "MK." Not all initials work as nicknames. Make sure yours rolls off the tongue. In general, the best initial nicknames are two syllables and end in either an "ay" sound like K or an "ee" sound like D
. Some people even go by just the first initial of their given name.