How do you guys manage to remember the inputs and outputs of photosynthesis and cellular respiration?
You might want to try visualise the situation and then input any missing links.
For example, the Light-Dependent Stage of Photosynthesis:
-Light energy (I) splits the Water (I) molecule
-Think "Okay, splitting means energy is released, ATP (O). Oh, but then this requires ADP + Pi (I ) to be made.
-Think "The remaining Hydrogen forms NADPH (O), but to do so thus needs NADP (I)
So, basically remember two main components from each section, and you should be able to do the above. Just try to picture where each substance would go, what it needs to create it, and the like. To continue on, then Light-Independent, the NAPDH must combine with the CO2 to produce Glucose. This requires energy, so ATP is input, thus ADP+Pi output. The hydrogen ions were given, so output is NADP.
However, it may be easier for you to just rote learn the inputs and outputs. Try to repeatedly say the inputs and outputs for each section, then cover to test yourself. Maybe even writing it out each time may be useful for you to remember.
Hopefully this helps