As a tips and tricks thread, here is my way of 'breaking' a slave. Making them obedient and lovey-dovey.
1) Head out and find an innocent (or not so innocent) target that tickles your fancy.
2) Beat them half to death, gently, of course.
3) Throw them in jail, then force them to cosplay as a butler with handcuffs while yelling in their face about how bad they're behaving. (cosplay optional)
4) Scream about the mistakes they make daily until you feel they're safe to place in commons, or they're max obedience. About 2-3 days with cosplay, max. if they get used to servitude quick.
5) Put them to work, and keep them in the lap of luxury with a ring and new undies.
6) Eventually you'll have an obsessed stalk-I mean, perfect slave. No brand or anything required. Just the occasional scream in the face to keep 'em in line should do.
As you go, they'll slowly love you, so long as they aren't under the luxury requirement. I find that the best time to ask about sex is around when their attraction hits 'Shows great loyalty to you as his/her master' or whatever. If it's a no go then, just try again in a day or two. It's generally pretty quick.
This is how I usually treat my 'collection', and, aside from the high ranked ones complaining once in a while 'cause they need absurd amounts of luxury, they are generally no issue at all. I keep 'em high-ish ranked to get their stats as high as possible, when I hit the cap, I drop the rank to conserve resources and annoyance.