Simple: 1. Make sure domain's ready for transfer: it's paid, unlocked, active email addy on record, and auth code/EPP code handy. 2. Start and fully confirm transfer with gaining registrar. Give them the code. 3. Confirm transfer with losing registrar. The tricky part is #1, especially getting the code.
That depends on the "story" behind the registration. If it's indeed registered through registerfly, you'll find it under modify contacts near the bottom. If it's actually registered through their enom reseller account, then get it from enom themselves. Do a WHOIS lookup and look at the line "registrar". That'll tell you where.