Building a Portfolio

I have lots of good photographs and have decided I'd like to sell them at art and craft shows.  But which of my photos should I try to sell?  I've got tens of thousands of photos I've taken over the years.  How do I winnow this collection down to a manageable size?  And what size should my portfolio b e in any event?

I've decided to settle on 20 as the size of my portfolio.  That means culling through my collection to find what I thin are the 20 most salable--if not necessarily the best--photographs.  My plan is to print these 20 in two sizes--8 1/2 X 11 and 11 X 14--and offer 10 of them matted and framed.  The remaining 10 I'll offer matted or unmatted so there will be several price points for buyers.

But, how do I get from tens of thousands down to 20 photos?  Here are the criteria I'm using to select them:

• The best photos taken locally in the area where I live and will be selling
• A few animal shots
• A few good railroad photos
• Some Civil War photos, since I live in Virginia, a site of much Civil War activity
• Some landscape and nature photos

A Civil War cannon at the Bull Run battlefield, with a caption

 My emphasis is on the pictorial--things people would like to frame and hang on their walls.  The problem is, that's always a guessing game until you see what people actually like and buy.  So, I expect the first few shows to be an opportunity to see what the public likes, versus what I think they ought to like.

Another Bull Run cannon, without caption

One issue--I sign some of my photos with a caption in script at the bottom and some I leave plain without such an annotation.  Which should I do?  Are the captions helpful or a turnoff?  What do you think?  Leave me your comments.  I'll value your ideas.