And it's no different for many of us writers who have developed our characters...their personalities, their appearance, even their friends and family. We place a lot of time and energy into breathing life into our heroine, hero, and secondary characters, so it's not uncommon (and perfectly normal) to have some reluctance setting out to create totally new ones for the next story.
I remember every one of my characters, even from stories I have no intention to try to publish. And I have favorite ones too...especially among the various heroes! After all, I can create the perfect man! Well, at least what "I" consider to be the perfect man in the particular genre I am writing. He can have green eyes, blue eyes, deep brown ones. Black shiny thick hair, or be a light sandy blond. It's painting a picture with words. Being a kind of mini creator.
I can give him a smooth temperament, a gentle as well as strong disposition. And make him a sharp dresser too. Piece by piece...he evolves. Describe your perfect man or woman!
Some Helpful Tips I've Learned For Creating Characters:
Photos. There are times some of us writers take features from photos of striking men and women found in magazines. It can't hurt to have a bulletin board of clippings of handsome men and attractive women to gain a more accurate creation/description of the character.

Travel magazines - perfect for descriptions of places we haven't been to but want to include in our stories. Or, of course, the Internet, which can take us to Tahiti or the slums in a matter of seconds with lots of photos. Save the ones that appeal to you most on a file in the computer for future reference.

Last but not least....it's a good idea to make the main characters likeable. Editors want to like them, and readers want to like them.