Kill as much stuff as quickly as you can on a player count as high as you can (think hmerdin / light sorc / blizz sorc). There is no "have this much mf to always find good items". The order goes
Kill stuff quickly on P1, increase DPS to a point where you can kill stuff quickly on p8, add mf in (200 is a decent amount, but it's by no means a requirement. If you need everything to increase kill speed, here's a few easy items to use in order to increase mf: 7*7 mf charms, gheeds, enigma. Boom, you're at > 150 mf without losing kill speed).
Or just make a week barb with a ton of mf and 75% find item to slaughter P1 (this is the most efficient way of farming items if done correctly).