I just added mine normally and had no problems. Tank is a 29g, other tank mates are cories, zebra danios, brilliant rasboras and a Bolivian ram ... not sure if that's a typical result, or if I just got lucky.
I agree with the above. If you don't have other bettas, you shouldn't have to do something special. You might if you have gouramis since they are related and sometimes don't get along, but a simple rearrangement of decor to help break up the line of sight and confuse any territories should help.