The one and only most important thing in game is to play according to events. If there is a troop training event running for the next 48h and CvC is coming up in 24h, you should wait with your troop training until CvC starts, to hit to kill two birds with one stone so to say. Playing smart is the most essential thing, as you maximise your outcome.
If you wonder what CvC is, I will tell you, its Clan versus Clan, where you just score points against one specific enemy of an enemy kingdom (EK). There is also a KvK (Kingdom versus Kingdom) Event and a KvKr (Kingdom versus Kingdom Revenge). In KvK you get points from doing stuff in EK versus in KvKr you get points from scoring points (e.g. yielding) in HK (Home Kingdom).
You don't need to learn that by heart, you can look it up in every events window:
You can also easily calculate the outcome of certain action considering this in your daily work.
Another important thing is to wear shields. It depends on what kind of player you will be. If you will be farming most of the time, you should buy longer shields, whereas as attacker you should have a lot of shortterm shields. But still a few longer ones between the events. The shorter the shield, the more expensive it is.
In the following topics, I will also describe certain things. If you have any question, please just post it here. I hope it helps and would be happy if you share your experiences too.
