Just some basics-
It really does not matter that you are in VA because a lemon tree would not survive outdoors there, its going to be spending its winters indoors.
It should be fine down to the low 40's or upper 30's though in a pinch.
Citrus doesn't like to sit in water, only water once the top of the soil feels dry, this might be every other day or once a week or more depending on the size of the pot/tree, amount of heat / light, etc.
When you water, soak it and leave it.
Don't water a little here and there: you end up with soggy soil on the top of the pot rotting the roots, and dry soil at the bottom drying out the roots.
As for fertilizer, there are special fertilizers made specifically for citrus with micro nutrients, but I personally just use standard off the shelf fertilizers mostly.