I reuse my organic soil mix, it gets better every time. You do it just like you did on the first mixing. Add amendments, stir, add water, let sit for two months. Some amendments you don't need to add every time, like greensand.
Take a look at your plants at the end of their grow and try to figure out what they were running out of. Was it N? Add more alfalfa, guano, and kelp. Was it K? Again, alfalfa, kelp, greensand. Was it P? Guano, bone meal, ect, ect, ect.
Hopefully you've cared well for the soil and not added any chlorinated tap water, the microbe herd should still be alive and running so no need to add more, just feed them. As always water the soil down with some molasses water.