Yeah, don't try an hop the same as with spds, a hop on flats is all about getting the front end up first, get this up nice and high then throw your weight forward, you are not pulling the back end up!
Practice by trying to lift your rear wheel by just throwing you weight forward.
For manuals, I have found a little pedal to get the front end up high helps you find the balance point, feather the bake brake a bit too.
Flats rule! ( I am an ex bmxer, so love em!)