[XKor]

Every person is different, and also not all subs/slaves are compatible with all doms. You can train a slave to modify his/her behavior, but if the will of changing some aspects of their personality is not in his/her nature, you'll be wasting your time.
Have in mind also that many people, specially in forums like this one, focused on dares, don't see the difference between being submissive and performing some dares when they're on the right mood. You should be upfront with what you want and be clear about your short and long term goals. If the submissive is not able to meet some short term requirements, you need to think it twice if you're doing something wrong or just the slave's profile does not adjust to your minimum standards. Be honest with yourself.
One of the common mistakes that we can make as Doms is that, since it's sometimes so difficult to find a sub, any kind of sub, we could insist on closing our eyes to the reality when we find one, but he/she is simply not for us.. Better let him/her go so both can search for a better match.
I'm not saying that it's your case, because I don´t have enough info, but it could happen..