Thread:Support/Requirements/reply

They're not set in stone and Siebrand or Nike can answer better, but in short and based on what they said in the past: 0) knowing what it is (see here), 1) needing it to do some work (e.g. "I plan to go through all MediaWiki core messages to ensure consistency"), 2) having an adequate experience as translator here, 3) having an adequate track of interaction with other users here (this is a tool to enhance cooperation and feedback).