When you curl your lashes put the mascara on first then curl. as the mascara dries it will stay in the curled position and solidify. it will stay curly all day long with no retouching!
My take on this is, from experience, if you apply mascara and then curl, you'll clump up your mascara and lashes wont separate.
What I do (although I have short lashes) is curl, apply mascara and then BLOWDRY.
You have to have a blowdryer with a COLD setting though, otherwise, you'll be burning your eyes with the hot air. First blowdry with the air blowing upwards lifting your lashes for a few seconds. Next, blowdry with the air blowing forward for a few seconds to push your lashes back for a more lifted look. This not only helps give a bit of volume but it also dries your mascara quicker so it'll hold longer.
It's sad but true that this is what my lashes look like when I only wear mascara and curl them. You can barely see on the picture on the left because they're not lifted, they're just flat and curling AFTER applying mascara takes away the thickening aspect of the mascara.