Make your fences taller

One of the easiest things to do is to buy new fencing panels to make your fences taller. This makes it harder for your neighbors to see into your garden at ground level. 

There are restrictions on how tall you can make your fences, so check local codes in your area. Usually, the limit is 8 ft, although many people tend to be below this. There may also be specific ordinances and regulations operating in your neighborhood allowing you to have taller fences. If taller fences aren't an option, you could also look into strategically placed privacy screens. These can also be a great way to reduce lines of sight and ensure that you remain private when using your back garden area. 

Add privacy window film

Another way to avoid being overlooked by your neighbors is to add privacy window film to your windows. Adding privacy film is most important at the front of your house, especially if you have windows at street level that people walk past all the time. You can also add frosted or patterned windows to your bathroom and other rear bedroom windows if you don't want people looking in. This can obscure incoming light while ensuring that your rooms remain illuminated.

Another thing you can look at doing is adding net curtains or cellular shades. These are another way of filtering light while also blocking sight lines from outside. These interventions shouldn't make your rooms feel dark. 

Outdoor hedges

If there are limits on the height of fences in your area, you may be able to get slightly taller privacy screens by using hedges. Often neighbours won't complain about these, and you'll be able to grow them maybe up to 50% higher than the surrounding fence.

You don't necessarily need to put hedges around your entire garden. Instead, you'll want to place them where line of sight is most likely. Use them to block sight lines. If you're not able to use hedges, you could also look into using trees. These don't block sight lines as comprehensively, because most trees have gaps in their coverage, but they can still be effective to give you a sense of privacy. 

Layer your defenses

Finally, you'll want to layer your defenses. For example, you could combine higher fences with window film and tall bushes. The idea here is to break sight lines at multiple points so that people can't see directly into your property. You can also put up fences around the front of your home, especially if you have street-facing windows. Again, these reduce sight lines from street level, although you may be overlooked by neighbours on the other side of the road from you.