Considering the fact that light constructs are magical, and therefore do not obey the laws of physics, I'm pretty sure we can safely say that they can do whatever they want. That said, we should probably establish some solid rules for them.
I had imagined the light control to be able to
A) create hard forcefields, which are unbreakable as long as Angel keeps applying power. Damage to the forcefield drains Angel's power, and as such enough damage forces her to drop the shield. It's shape can be pretty much anything Angel can imagine, allowing it to become quite sharp. They are moved by a 'telekinetic' force strong enough to exert 1 ton of pressure. Multiple things can be moved at once but this requires extensive concentration, and there is a limit to how many separate constructs Angel can simultaneously control.
B) energy can be gathered and concentrated to form laser beams. These beams are pure light and heat, possessing no mass, and as such damage objects by melting them. They can melt through steel in a matter of seconds, but higher intensity beams cause greater strain on Angel.
Potentially photokinesis could be used to create illusions, but this seems like something Angel wouldn't practise. As such while technically within her capabilities I don't think she'd be very skilled at it.
Just throwing in my 2 cents.