Certain casinos might ask players to sign up to receive an invitation to participate. In contrast, others may limit tournament entry to VIP or loyalty program members. Casinos also organize free slot tournaments. In these cases, all you need to do is register for the competition.
While there are betting strategies for slots and tips to manage your bankroll and potentially increase your chances of winning, there is no strategy that can consistently beat the odds in the long run. Slots are games of chance, and outcomes are random.