You can receive bitcoin by
- Offering a product or service in exchange for bitcoin
- trading bitcoin for fiat currencies like USD, EURO, AUD
Create a new bitcoin address with the software called a public key.
Post that public key wherever you offer your product or service.
There are also many merchant services that you can integrate into most shopping cart software which you might be using. i.e.
Buying bitcoins.To buy bitcoins from your local flat currency please see this fantastic list of exchanges.