Originally Posted by
TravelPhotographer
(MIA, have various airline miles & hotel points if helpful)
(primary purpose = lots of stops with lots of photo opps, some free time to explore)
first time shopping river cruises;
is there tutorial out there for finding best deals?;
is there consensus best vendors offering
lowest prices best quality balance...?
any advice-comments appreciated...

Find a travel advisor who works on river cruises and tell them about your likes and dislikes (such as luxury? budget? relaxing? adventure? active? museums? history? art? music? foodie? counties or rivers you especially want to visit?). A good TA can help match you well.
Personally, I am not a fan of Viking, who advertises the most. They have fare policies that are much stricter than industry standards (requiring final payment earlier, of example). Having said that, I know many people who have been happy with them.
AMAWaterways is highly regarded and easy to work with. They have a wonderful free cruise offer for "Frontline Heroes"--nurses, doctors, pharmacists, hospital workers, EMTs, lab technicians, paramedics.
Otherwise, a good starting point is
Ralph Grizzle's blog.