This is hard to do. Assuming you are talking about Fable II, there are a number of things you can do, but it will take some time.
- Donate at the Temple of Light; 1000 gold at a time gives the best value-for-money morality boost. 25 Good each time. This is only possible provided you didn't destroy the temple in the Oakfield Massacre.
- Complete the repeatable side quest/job Slave Rescue. For each batch of slaves you rescue, you get 30 Good.
- Give money to beggars.
- Look for villagers that will give you gifts for a high love or high funny statistic and earn these gifts. 10 Good for each positive gift earnt.
- Kill monsters that are near villagers. Sometimes this will register as 'saving' the villager and will grant 10 Good per villager. The best regions for this are Bower Lake, Brightwood and Rookridge when the travelling traders are attacked by bandits.
- Visiting your spouse usually gives about 10 Good.
- Having sex gives about 10 Good, protected or otherwise.