I'm on redbubble and as yet I haven't sold anything either....However it's up to you in how you approach it......You have to build a watch list and then people will start watching you, you have to be an active commenter and you should submit your best work. It's important to bear in mind the number of people on there too...thousands!! LOL. According to them they have shipped 73,500 items of art to 71 different countries in the last 12 months.
Realistically you are a small fish in a HUGE pond....it's not about quality of work or thinking you're good enough (I've seen sone real c..p sell), so you won't make a fortune!
I enjoy it because of the people I know and those I have met through it....it's a good testing ground for your work although you won't get good crits like you do here! Infact if you find me there you'll see work that I have never posted here.
There are groups covering many different types of photography and art and yes there are landscape ones!
One thing I know for sure is that you won't get rich there LOL...
