Whether you're home or away, windows can be an advertisement to thieves. Most garden-level apartments are outfitted with window bars and locks, and you'll want to double-check or replace those as a tenant. But there's also the preventive measure of making sure you and your home aren't targets to begin with.
Again, you'll need to balance your security concerns with your need for light, which means considering options: A sheer café curtain or sash provides cover during the day, but you'll need something a bit less inviting for nighttime protection.
Your patio or garden decor should contribute comfort and style as you maximize whatever outdoor areas come with your home, but it can also be stolen or, worse, advertise the probable belongings within. Keep outdoor furniture and furnishings to a minimum, or stick with disposable outdoor furniture, and always turn off outdoor lights when they're not in use.