I am at a stage of my research where I will start recruiting participants soon. My sample is reasonably healthy older adults (55-70 years). I have given a number of health talks in community centres where people could sign up for the study. However, relatively strict inclusion criteria will be applied. Hence, I will need to exclude people. Now, I would like to get some idea on how to best do it. People should still feel valued but I also need to make sure I conduct valid research. What are your experiences and suggestions?