There are two basic types of games

1) Games of chance, which depend on luck and not the skills of a player. 2) Games of skill, which depend on the skills and not the luck of a player.

Craps, Roulette, Slot Machines, Keno, Bingo, Lottery and the Big 6 wheel (wheel of fortune) are games of chance. What happened on the last throw of dice or spin of wheel does not affect the next event. Each event has the same odds (when you throw a coin the chance of throwing tails is always 50%), is independent, separate and not related to the preceding or succeeding event. In these games the dice, wheel or ball cannot remember what happened and you cannot calculate with it. A gambling student would call games of chance: events of independent trials. 

Games of Skill

Blackjack, Baccarat, Video Poker, Regular Poker, Sports, Horse Racing are games of skill. What happened before does affect what is going to happen next. For example, if all the aces have shown up in the first round of blackjack, you know that no more will turn up until the deck is reshuffled. Playing perfect strategy therefore will increase your chances of winning. In these games you have to be aware of what is going on, make calculations and get informed before playing.

Players beat themselves

It has been proven that most losses at gambling are the result of poor playing, strategies and money management. The smarter you play, the more lucky you'll be. So get informed. Read, gain knowledge, practice, be aware of the house advantage and win.