This is what I've heard works well: be on time, listen to what they have to say, surprise them with something nice every now and then to show you care and think of them (but be creative and take clues from your conversations), work hard and supply her with financial stability and a nice home, speak kindly of het family even if you can't stand to be around them... oh, just wait, were we talking about girlfriends or service providers? 'Cause overall, the service provider will cost you much less in the long run.