Here are 4 things you should do to become a better player:
1. Know what the cards do.
2. Know your deck.
3. Know your opponent's deck.
4. Know the board
I call these the cardinal rules, because they apply in every game of dominion.
1. Know what the cards doThis sounds like an obvious thing to state, but it is of utmost importance to understand how the cards work. On the most basic level you should understand things like what happens when you play a young witch or a fool's gold. This is a real issue when you are introduced to new cards like those from a new expansion and it takes a while to learn all of these new cards. It sure took me a long time to finally understand what Jack of all Trades does. Obviously you can acquire this knowledge by playing with the cards, but notice that sometimes reading the cards is not sufficient to understand what they do (Did you understand what tournament did the first time you
read it?)
Once you have a
basic understanding of the cards you can move on to having a
good understanding of what the cards do. This encompasses things that are not obvious from reading a card. For example: (1) playing outpost on an outpost turn will not give you a third turn, and you will only draw 3 cards for your next turn; (2) playing King's Court-Wharf will give you 6 cards this turn and next turn, but playing KC-KC-Wharf-Wharf-Wharf will not give you 3x3x2 cards next turn. These non-obvious interactions are probably going to become clear with the more games you play. The dominion strategy list of combos is also a good source of information. A good understanding also means that you know in what order you should play your cards. A simple example is venture before bank, a more complicated example is with cartographer, venture, loan, moat, scheme.
Knowing what the cards do also covers
remembering what the cards do. Pawn isn't just +1 card, +1 action and Tournament isn't just a gateway to followers. You can use Pawn for +1 card, +1 buy and you can use Tournament to grab a Diadem first even though you usually do not want to. Try to keep all of the uses of a card in your bag of tricks. For example: (1) After all of the Prizes are gone you do not need to reveal a province when you play a tournament, so you can avoid taking a Duchy; and (2) You can Mine a gold 'down' into a potion (in order to keep your Alchemists, say).
Similarly, you can usually discount cards like Thief, Bureaucrat and Possession when looking through the opening setup, but not always. So don't forget about them as even they shine sometimes. (Yes I know I put Possession in the same category as Thief and Bureaucrat. I mean this in the sense that these cards will rarely help you win the game and you can usually just ignore them. I do understand though that an opponent with a Possession is scarier than an opponent with a thief.)
2. Know your deckThis is such an important thing to know that it has its own article:
http://dominionstrategy.com/2011/06/24/guest-article-deck-control/Getting good at this will change the way you play. I have often passed on playing my Upgrade because I knew my deck well. I have also passed on playing Wharf. It is not often that this happens, but when it does happen I know that I have (probably) avoided some pretty terrible action clashing. The point here is that skill (of knowing your deck) can help mitigate the negative effects of "luck".
3. Know your opponent's deckThis is the complement to rule 2 and much of the same techniques apply- Know what your opponent has bought, how many points they have, know if they have played their big cards (gold, nasty attack, wharf, etc.), how many cards they have left (roughly) until a reshuffle, how many cards they have in hand, etc. Of course the knowledge you get from your opponent is incomplete (they don't show you what victory cards they have in hand, they don't have to play all of their action cards, you can't count their deck, etc.) but you can still get some information.
The most obvious way to use this information is with Possession. If you haven't seen their pile of gold and KC yet, go ahead and possess them. If you have reason to suspect that they have a bad hand (maybe you have seen all of their good cards so far) then maybe you don't want to play Possession. Similarly, know how many possessions your opponent has left in their deck! If your opponent is down to 4 cards in their deck and you still haven't seen their second possession then maybe you buy that province and discard all of your treasuries (instead of putting them on top of your deck).
Smugglers is also an interesting case. Suppose you and your opponent both open silver/smugglers (like the awesome people you are
). If you haven't seen their smuggler by turn 4, you know it is coming on turn 5. You can choose to buy that Tournament as usual (which will get smuggled), or maybe you choose to buy a silver instead, so that you stay up on tournaments. (N.B. I'm not saying that you should try to win the tournament race early, but that you should be aware of what your opponent will do).
A third application of the rule 'Know your opponent's deck' is 'don't let your opponent know your deck'. Well, what do I mean here?
Don't do things you don't need to do, especially when it gives your opponent information about your deck. For example if your hand is --crossroads, crossroads, gold, curse, potion -- there is no need to play your crossroads; doing this will just show your opponent that you got a lot of your crossroads together. Also in this example, don't play your potion if you don't need to. Why should you let your opponent know for free that you won't be able to buy a golem on this run through of your deck?
Some cards that lend themselves to needless play: crossroads, shantytown, smugglers (when your opponent didn't gain anything).
4. Know the boardThis covers basics like: "What cards are on the board?" and "How many cards are in each supply pile?"
Your knowledge of the board should include obvious things like is there any source or +actions, +cards or +buys, but you probably already include this in your first turn scan. (Remember that contraband gives +buy). Non-obviously though, you should know something about the black market deck (if it is present); are there game changers in the BM deck? Victory cards? Possession?
I love three-piling the game. I seems like a very sophisticated way to end the game. Fortunately for me, many of my opponents are not looking for a three pile end. Especially in games with +buys and cheap cards be mindful of how close the game is to over. In games with
tons of buys and cost-lowering, you might even want to end the game by buying all 8 of the initial estates! One of the most overlooked aspects here is the curse pile. It does count towards the end of the game and in games with curse givers there is a very good chance that the curse pile will empty. Don't overlook buying a curse (or two) to end the game.
I hope that adds to the way people play the game. Also, I'm sure that I forgot some other cardinal rules (Don't commit suicide, ...) but I will add them if people want.