Curling stubborn, straight hair
The type of hair I have: naturally very straight, layered a bit and boob-length at the longest. It's very fine in texture so my hair is often limp or flat. I use heat products (blow-dryer) only very occasionally and haven't dyed my hair in almost 3 years (in short, my hair is pretty healthy). The catch is that my hair is very stubborn, it does not hold a curl well and does not curl easily in the first place. I have tried putting my hair in a bun or french braiding (no product) and sleeping in it; when I wake up my hair is very pretty but it straightens itself within an hour or two.
What can I do and what products do you recommend to get me the hairstyle I'm after? If you couldn't tell already, I'm pretty clueless about styling hair. Any tips, tricks, or general methods (I have hot and velcro rollers, a straightening iron and a curling iron) to use will help. My biggest concern is my hair losing the curl after an hour.
Here's an idea of what I want: