Blackjack is a game of skill, and when played as such, can be your very best bet for actually making money in a casino (not a common occurrence).
Using basic strategy can keep you nearly even with the house, it is not uncommon to find blackjack games that carry a house edge of 0.5% or less. Basic strategy is playing rules based on the cards in your hand an don the dealer's upcard.
Basic strategy will maximize your advantage. Deviating from basic strategy will cost you money. It can't be put any more simply than this people.
Hard Hands
9 or lower = hit
10 or 11 = Double down if your total is more than the dealers upcard; otherwise hit.
12 - 16 = hit when the dealer's upcard is 7 or higher; otherwise stand
17 or higher = stand
Soft Hands
13 - 18 = double down when dealer's upcard is 5 or 6
17 or lower = hit
18 or higher = hit when dealer's upcard is 6 or less; stand when dealer shows 7 or more
19 or higher = stand
Pairs
Always split a pair of aces or 8's
Never split 10s, 4s, or 5s
Split all other pairs when dealer's upcard is 6 or less