The easiest way to make sure you are able to find someone you are interested in again is by either adding them to your Favorites or like them. This way you will be able to view them again by clicking the appropriate link under the Activity menu.
For more information about Favorites, click here.
For more information about Likes, click here.
If you did not do either of the above, you may still be able to find a particular member if you change your search criteria to be as specific as possible about what you remember about that member. You can also search for another member using the Member Number search, if you have this information. For more information about searching for members, click here.