Having a rectangular (or square) lot is advised in Vastu. If that's not the case, you can create a rectangular wall, fence, or hedge around your home, leaving some bits outside the fence. This will help protect your home and its energy. If you already are fortunate to have such a protective barrier, check it for any needed repairs.
To enliven the protection of your home, you can create your own ritual. One of my clients in New Mexico loved the idea of enhancing and reenlivening the protective feature of her post and wire fence around her property, so we devised a ritual. Walk clockwise around the perimeter, thanking Vastu Purusha, the soul of your home, for protection and support. OM NAMO BHAGAVATE VASUDEVAYA is one protective chant you can use while walking around the property, or use any words that come from your heart. Carefully burn incense or sage as an offering with a bowl underneath it or spray rosewater in the air as you walk. If you find any trash or dead debris, clean it up. Cleaning is an honoring of the environment and always improves the energy.
Never keep trash or piles of unfinished projects in the northeast of your property. Keep that sacred zone clean, fresh, and unencumbered. Ideally keep your trash, compostibles, and recycling bins outside of the north and east also. They should be stored in the south or west, if that's possible.
Keep everything maintained and in working order that can be seen from outside your property. And of course it's best to treat the inside of your home that way too.
I look at the land, placement of trees and water bodies, the shape of the lot, and many other factors when doing a Vastu consultation. I then advise my clients on more ways to improve the supportiveness of their home with Vastu knowledge.