Thanks, everyone for the advice and encouragement...I know my pics are not very "microstocky" - I'll try to add some quality still lifes of various objects to the mix.  I've also taken to carrying a monopod with me to help with focus issues.

I'm very much a newbie with only a dozen or two photos accepted on the "major" sites.   That said, I've had the best luck with acceptances on Shutterstock (sales as well) and after 4 attempts am YET to get on iStock      .   BTW, I also submit on 123rf, dreamstime, fotolia, bigstock, canstock, and cutcaster, all with varying degrees of success.