Generally speaking lift = AOA * Airspeed.

Except when accerlating or decelerating up or down (i.e Beginning or
ending a climb or descent) the lift = weight of the airplane. Check out
the 1st few pages of any physic book to verify this. Another way of
thinking about it is that the tension on an elevator (Building elevator
not an airplane elevator) cable always equals the weight of the
elevator and occupants even if the elevator is moving. It changes only
as the elevator accelerates or decelerates.

so since the lift seldom changes the only other 2 variables are AOA
and Airspeed. If you slow down you must increase the AOA to maintain
lift. If you decrease the AOA you must increase airspeed to maintain
lift.

The Rate of Climb indicator directly show excess or Power in a climb or
insufficent power (to maintain alt) in a descent.
Movement of the Rate of climb needle (decreasing or increasing) shows
changes in the amount of lift generated.
A G Meter will directly show the amount of lift being Generated. i.e.
2G = 2x gross weight of the airplane is being generated.

Hope that helps a little

Brian
CFIIG/ASEL