One of the most important things you can do to get better is to get a sense of whether you’re in the beginning, middle, or endgame. When there are 20 points or so remaining in the game, and if you still have a bunch of cards in your deck, buying the construct that costs 6 and lets you draw an extra card every turn is almost never the right thing to do, since it’s only giving you 2 victory points for 6 runes and you’re unlikely to draw it before the end of the game, much less get a second turn with it in play (which is where you start getting a benefit from it). Similarly, cards like Druids of the Stone Circle and Arha Templar can be useful on occasion during the game – you definitely got some use out of the Templar – but in general they can get in your way and most of their benefit comes from being worth 3 VP.
There are a couple of exhibition match threads that might be useful for you to read:
Good luck! I’m sure you’ll get better quickly.