According to the protocol approved by the ethics committee, you can recruit participants in different ways:
Word of mouth: you can ask friends and colleagues to participate as volunteers.
Flyers:
Mailing lists
RPS
If specified in the ethics protocol, participants need to be compensated for their time. They can be either paid, they can be given course credit or they can obtain some other incentive (e.g. participate in a prize draw). To manage experiment participation, recruitment, and course credit, psychology students can use the RPS system: