Here you go
"Smear Honey on a Yellow Tree and wait 6 hours WITHOUT changing the DS clock or using a different DS. You have a 20% chance of finding a Combee (save before checking the shaking tree). If it is not a Combee, catch or KO the Pokemon, smear more Honey, save, and try again.
If you reset after checking the tree and retry, it will always be the same Species that appeared on that attempt (like if you see an Aipom, it will be an Aipom if you keep resetting for that use of Honey), but not the same Level, Nature, or Gender. This is important because Combee are only Female 12.5% of the time (1 in 8 chance every time).
Once you find a Combee, you can easily reset over and over for a Female."