Etsy is a good place for art work. You can showcase your items which would bring lots of traffic. There is a fee for this but it is worth it.
I know you could sell this type of stuff on ebay, it probably would do very well since ebay is so big it reaches alot of people. There is a website called etsy.com that sell handmade items. That is where people go for specifically handmade item and supplies.So I would think paintings would do very well there.
I have had lots of friends who are artists who sell there artwork on deviantart.com. It is a great community and a lot of individuals who love artwork will purchase your work if they like it.
Well for starters you could get a acount on ebay and sell it ther or go to kreggs list.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.