darkSpyro

As children we are given ideas by our peers and our elders about how we should be, who we are and how the world is. Some of these could be easily dis-proven, some are simple and make sense and some we hold onto even though we dont know why.
We all have ideas built into us on how to act and various things, but how do you stop believing in one of those ideas?
If there was something wrong with an idea built into your mind, something like self-hatred, or racism or something like that, how exactly would you stop believing in that?

Well that depends highly on context. Certain ideas are put into your head because they're vital to know from a young age (e.g. fire is hot and you shouldn't touch it). Other ideas are based around religious beliefs or other things relating to parents. And some are just things that other people have said a lot so it got into your head that it must be true.

In your case, the third and final option is what ails you. People would say something repeatedly and you've now gotten it hard-wired into your head. What you then have to ask yourself is just how much these words matter anymore. How long ago were they said to you? Who said them? Are those people still influential in your life to this day? Has anyone ever suggested the opposite? Are they influential to this day?

In your case it's a matter of thinking those things over and looking more towards what is said to you in the present. If the people that said these things in the past don't matter to you now, you should focus more on the people that do matter in the present and what they have to say about you. It's tough at first, and it's even harder when dealing with depression (where you may not accept anything people say unless it's negative), but putting the effort in can go a long way and you might find results.

As for other things like religious beliefs or morals, that goes far beyond what you're dealing with and is a completely different can of worms that isn't really worth opening right now.