Tips goldblivion

Relative value of resources:
-Gold: 7 nuggets (by the game rules)
-Material: On one hand, some cards offer either 4 nuggets or 1 material. On the other hand, a development card produces 0.5 materials or 1 gold per round. So one material is worth around ~3 nuggets. Therefore you should rather develop material instead of gold production.
-Magic tokens: They are highly situational, on average worth ~3.5.
-Dice: By averaging over the sides, a dice is worth slightly more than 2.

Villages:
The left village has a side where you pay 2 and gain a dice, so it pays for itself and you gain a destroy action. You should almost always use it when available, otherwise you can expect your opponent to do it. For the right village, the side which converts 2 materials in one gold should also been taken in general before your opponent can. The other sides are rather situational, so you can expect those actions to be open most of the time.

Synergies:
-Elves: Elves have the highest synergy, so avoid bloating your deck with non-elves if you plan elves as your long term strategy. As an opponent, pay attention and try to destroy the most synergistic elf cards like "Eve and Lily" from the market.
-Dwarves: Only 2 out of 34 combat cards in the deck profit of this synergy, so you should only go for this opportunistically.
-Humans: Since it is usually best to sacrifice the basic human workers for development early and the synergy reward comes mostly with buildings late in the game, it is rather some nice bonus than something to rely on.
-Buildings: Negligible

Combat:
-Even losing a combat is good since it improves your combat deck by allowing you to destroy your weaker soldiers.
-The forest enemies provide good rewards for relatively little investment in military. Even though the mountain enemies provide better rewards, they require a significantly bigger investment and are much more risky.

Deck management:
For the last few rounds, you can trim down your deck so that you have an arbitrary number of cards which each draw another card plus 4 non-drawing cards. In the next round you are then guaranteed to draw at least one of the drawing cards and with that you can consistently draw your entire deck. Before you play the last drawing card you can buy another card, put it on the top of your deck and then draw it and play it immediately. This is very effective since most cards are paying back more than their cost just by playing once.

Games between skilled players almost always end on the 6th round, so don't waste resources building up a super long term engine.