How about offering more benefits to premium members to increase membership. For example, premium members can have the option to have a 'warning sound' when it is their turn. Or, premium members have unlimited 'add time' function in a match. You could also even consider allowing premium members to have the ability to quit a game. From time to time people need to leave. If you made a function that allows premium members to do this (if if were to be abused, you may need to consider adding restrictions). You could also extend that function to non-premium members, only if they are in the game with a premium member then they have the opportunity to leave the game early. This would decrease waiting time for premium members, and give non-premium members an extra feature from time to time.
How about offering more benefits to premium members to increase membership. For example, premium members can have the option to have a 'warning sound' when it is their turn. Or, premium members have unlimited 'add time' function in a match. You could also even consider allowing premium members to have the ability to quit a game. From time to time people need to leave. If you made a function that allows premium members to do this (if if were to be abused, you may need to consider adding restrictions). You could also extend that function to non-premium members, only if they are in the game with a premium member then they have the opportunity to leave the game early. This would decrease waiting time for premium members, and give non-premium members an extra feature from time to time.