|Excuse my horrible drawing|
For starters, it's probably best to wear patterned bows with something plain. We don't want stripey bows adorning our spotty dresses because frankly, we'll end up looking as over decorated as Osherwat (apologies to his fans). Matching in colour is often a good idea, but sometimes a complimenting colour is great and can really make the bow stand out. And example is black bows on white - these look great, but I wouldn't go so far as to start mixing green bows on blue clothing, but that's up to you.
Socks with bows are adorable and, in my opinion, pretty sexy. Long socks with bows are pretty much the god tier of all socks, the above photo as evidence. I'm not a huge fan of bows on the shorter variety of socks, because it puts you in real danger of looking like a three year old. However, if you are blessed with the ability to be asian, you can pull of this look as simply kawaii.
I think this is a great example of bows in hair not looking childish. If you can get your hands on a bow that looks sophisticated and simple, it'll look great in your hair. Again, I'd be careful with colour choice, but mostly, pick something that people will actually be able to see against you hair colour. If you have the perfect bow, but it's not a clip, you can always thread it onto a bobby pin. The above photo does show an example of wearing bows in more than one place at a time (the earings and the hair), but I'd also be careful with this.
Generally, to avoid looking as over adorned as this:
|That's not to say she doesn't look adorable, but I don't know if this look will translate well anywhere that isn't an anime festival, let alone real life.|
I'd stick to wearing a bow in one place at a time.