In general, you have about 1 chance in 8,000 to win a jackpot on a straight three-reel machine. The odds on video lottery games and the like are even more astronomical. The bad news is that those odds won't change significantly no matter what you do. The good news is that you can take some steps to make playing more enjoyable.
First, look for the highest payout percentages you can find — 95 percent or higher. Second, observe other players and the machines they play. If you watch for a while, you can get a pretty good idea of where the looser machines are. It also doesn't hurt to ask the attendant which machines the locals prefer; regular players won't waste their time at persistently tight machines. Third, decide before you begin how much you're willing to invest in a machine before it starts paying out. If a given machine isn't paying out something on every fourth or fifth pull, you might be better off looking for another machine.
Finally, look at playing the slots as a form of entertainment rather than a get-rich-quick scheme. If fortune favors you, that's terrific. But if it doesn't, at least you've had some fun.