Erm...
Write down G. Answer these questions:
1) How can :delta: G < 0?
2) How can :delta: G > 0?
3) In what case is a reaction spontaneous?
4) In what case is a system in equilibrium?
Enthalpy is interpreted as (for an undergraduate, me being one) bonding strength.
Entropy is, like you mentioned, a measure of order.
P :delta: V can be useful (reversible). Consider a simple piston with no gas exit and volume V. If you compress it to V/2 and put an appropriate weight on top of it so the piston pushes it back to ~V, has the piston done useful work?