To play online slots like a pro, start by choosing reputable casinos with high payout percentages. Familiarize yourself with the game rules and paytables to understand symbols and bonus features. Set a budget and stick to it, using strategies like the "50/50 rule" to manage your bankroll effectively. Take advantage of bonuses and promotions, but read the terms carefully. Play for fun rather than solely for profit, and know when to walk away. Lastly, practice with free versions to hone your skills before wagering real money. Happy spinning!