making an advanced tips page for people needing help who are over lvl 2..
If you have built high level heroes, and then realised that they aren't very good (food), then don't worry, and don't restart the game. The characters can be used later to build higher level heroes.
If you see a hero that you really like, before you spend anything on building that hero, check the Faction divided tier list. It is an updated guide on the power of the heroes. If you find that the hero is rated as food, you shouldn't upgrade that hero. If that hero is rated high, then you should build that hero.
Building strong heroes:
If you find a strong her that you want, you can follow this guide to make the hero high level easily. First, search all of the shops for that hero. If you find any of that hero, then save the required currency to make it. Next, to get a six star, create the other hero that is required. Next, save as many gems as possible throughout any event that doesn't give that hero as a prize. When an event comes along that includes that hero, spend all the gems that you need to get the hero.