In general, if you want to sell to most of the "stock photo" sites do not send photos of your pets, sunsets,seascapes, etc.

 

The majority of stock photo buyers want to use photos in business or commercial mediums. They are more interested in a photo of 2 hands in business suits shaking with a white background than the best photo of your dog.  However, if your dog is photographed with a white background doing somthing commercially interesting, that is another story.

 

If you are selling to sites that sell and ship prints, then landscapes, nature photos and maybe even your dog should sell well.  The key to remember is to read what the site is about.  Most sites will tell you what they want and need for photos so that no one wastes their time.

 

Many of us picked up our first cameras at a young age and began snapping pictures of everything that came in view of the lens.  These early pictures were all "snapshots". Some early enthusiasts are still taking snapshots and having a geat time doing so. To those camera buffs I would say "keep enjoying your hobby, but do not look to sell your pictures".

 

There are always others that evolved from the snapshot to the photograph.  They have a special talent, have pursued their craft in earnest. They most likely have taken courses and devoured any new information about photography they could find.  This is the group that has a chance to sell their photography.