Well, really, there are two types of decks in dominion. Money (and to a certain extent slogs) are looking to rush VP. Engines, on the other hand, are looking to build up as big as possible before ending the game.
Consider the simple board of Village, Smithy, Market, and Chapel.
Money:
The strategy here is clear - open Smithy/Silver, pick up some treasures and then buy Provinces early and often.
Engine:
The engine wants to draw deck and then build exponentially. Here's an example of the concepts an engine might consider. Please forgive any typos I may have made.
To this end, let's define a series of concepts:
Cards to draw deck:
Terminals:
Villages:
Coins in deck:
Buys:
VP in supply:
VP deficit:
Coins/Buys to end game:
Estimated opposing coins/buys:
On turn 1 with a deck of 7 copper/3 estate, this evaluates to:
Cards to draw deck: 5
Terminals: 0
Villages: 0
Coins in deck: 7
Buys: 1
VP in supply: 80
VP deficit: 0
Coins/Buys to end game: 64/8
Estimated opposing coins/buys: 3.5/1
Since drawing deck is the early game priority, the clear opening is chapel, paired with either Market, Silver, or Village.
On turn 6, the deck might look like 4 Copper, 1 Estate, 1 Silver, 1 Market, 1 Village, 1 Chapel
Cards to draw deck: 2
Terminals: 1
Villages: 1
Coins in deck: 7
Buys: 2
VP in supply: 80
VP deficit: -2
Coins/Buys to end game: 64/8
Estimated opposing coins/buys: 6/1
Here, a Smithy would be a high priority in order to get to the point of drawing deck
On turn 10, the deck might look like 1 Copper, 3 Silver, 2 Gold, 2 Market, 2 Village, 1 Smithy, 1 Chapel
Cards to draw deck: 0
Terminals: 2
Villages: 2
Coins in deck: 15
Buys: 3
VP in supply: 74
VP deficit: -9
Coins/Buys to end game: 56/7
Estimated opposing coins/buys: 7/1
There's still plenty of time left in the game, so building more with Market/Smithy/Gold looks good
On turn 12, the deck might look like 3 Silver, 4 Gold, 3 Market, 3 Village, 2 Smithy, 1 Chapel
Cards to draw deck: -1
Terminals: 3
Villages: 3
Coins in deck: 21
Buys: 4
VP in supply: 62
VP deficit: -21
Coins/Buys to end game: 40/5
Estimated opposing coins/buys: 7/1
With VP running low, it's time to start looking at greening. Something like Province/Village/Smithy/Gold looks solid
On turn 13, the deck might look like 3 Silver, 5 Gold, 3 Market, 4 Village, 3 Smithy, 1 Chapel, 1 Province
Cards to draw deck: -1
Terminals: 4
Villages: 4
Coins in deck: 24
Buys: 4
VP in supply: 53
VP deficit: -18
Coins/Buys to end game: 32/4
Estimated opposing coins/buys: 6.5/1
Now it's really time to take points, while defending against a possible province. Buy: Province/Province/Village/Smithy
On turn 13, the deck might look like 3 Silver, 5 Gold, 3 Market, 5 Village, 4 Smithy, 1 Chapel, 3 Province
Cards to draw deck: -1
Terminals: 5
Villages: 5
Coins in deck: 24
Buys: 4
VP in supply: 35
VP deficit: -12
Coins/Buys to end game: 8/1
Estimated opposing coins/buys: 6/1
With 1 province left, the engine takes the win with Province/Duchy/Duchy/Estate