The question I get asked most is whether a statement ring actually works with other rings on, or whether it needs the rest of your hand left bare. Honest answer: it needs one plain band nearby at most, otherwise your hand looks like a jewellery counter had an accident, and not in a good way.
Colour wise, I've gone off anything too shiny and bright gold, because it reads cheap under normal kitchen lighting, never mind anywhere dimmer. A worn, slightly matte gold or an aged brass finish looks like it has history even when it's three weeks old, and that's what you want from a big ring. Mixed metal ones, where there's a dull band and a brighter stone setting, are more forgiving if your hands change colour with the seasons, which mine absolutely do. Stones in deep green, amber or a smoky grey sit better across the board than anything pale, because pale stones show every knock and every bit of hand cream residue, and you will have hand cream residue, we all do. The test I do in a shop is hold it under my chin like I'm checking a tan, not under the shop's spotlights, because spotlights flatter everything and tell you nothing.
Once you're past colour, it's all in the weight and the setting. Pick it up and it should have a bit of heft, not feel like it would bend if you knocked it on a door handle, because that is exactly what will happen to it eventually. Run your thumb round the inside of the band, if there's a seam you can feel or a rough bit where it's been soldered, put it back, that's where it'll snap or scratch you in six months. Check how the stone sits, pushed in and held by proper claws rather than just glued into a setting, because glued stones come out in a hand wash and then you're fishing round a plughole with a torch like an idiot. A statement ring should not clatter when you tap it against another ring, it should sound solid. As for what to avoid wearing it with, skip anything with a lot going on at the wrist or neck at the same time, chunky bracelets or big earrings turn one good ring into noise, and skip wearing it with gloves you actually need to use your hands in, because fiddly settings and winter gloves do not get on.
Next time you're looking, forget the stone colour first and check the inside of the band for a smooth, seamless finish, that's what tells you if it'll last.