security for the modern home

[Sunna]

my house has 3 ground floor doors all with glass panels in plus large windows at the front and the back and a small one on the side .
to make my home secure with out it looking like a fort is impossible .
we all get away with this because on the whole somebody trying to get in would be seen or heard but after shtf raiders would not worry about noise or being seen .
so what could you recommend to boost a homes security with out it looking like a fort .
i rent so nothing to mad please