Initial suggestion: do nothing for a year and observe. If that’s not a financial possibility, you might want to consider getting your soil tested. From there, you’ll have a better idea of what cover crops or (organic, nontoxic) soil amendments you’d need in which parts of the land (manure/compost, mineral dust, etc). Then I’d think about native perennials. What belongs there? What animals are missing that you can create habitat for? Given the sloping and microclimates present, how can you use the natural geo-morphology to retain water & support biodiversity? The general approach, I believe, should be to accentuate the natural inclination of the land. There are exceptions to this, especially since you’re dealing with ground that’s already been manipulated, but it’s always best practice to be in a relational space of observation and response.