Check out the community guide section of the forum. There are a lot of great tips for newbies.
Someone from my guild created this helpful guide -
(Speaking of which… make sure you join an active guild. As you level up and get more kingdoms leveled and have more gold to give you can see how much you make a week and find a guild whose requirement you meet that might have a higher activity level than a starter guild. The better the guild the more rewards you will receive. It’s imperative you do this immediately as it’s the only way to get premium currency easily)
Also if you have a bit of time and like to watch videos, here’s a great guide geared towards newbie tips:
And of course @Tacet has great tutorials/videos as well. Check out his channel via profile.
Welcomes to gems of war!
Edit: cleaned up the links, thanks to @actreal for the tips! I’ve never used a forum where you can’t use the URL at the top of the browser to get to the general post and start at the top!