When looking for the best online slot RTP, it is crucial to consider the return to player percentage, which indicates potential winnings. Researching and comparing RTP values across different online slots can help in finding the most rewarding games. Factors like volatility and bonus features also play a significant role in determining the best online slot for high RTP. Players should prioritize games with a high RTP to maximize their chances of winning big rewards. Keeping track of the RTP of favorite online slots can lead to a more profitable gaming experience.