I always hit this issue: I have a Raspberry Pi I want to set up, but I don’t want to break out the cables to hook it up to a monitor and keyboard. Luckily, the Raspbian OS actually has built-in features for this. Just follow these steps:

# Extract the Raspbian OS Lite image
xz -d <image>-lite.img.xz
# Flash the image to the SD card
dd if=<image>-lite.img of=/dev/sdX bs=4M
# Mount the boot partition
mount /dev/sdX1 /mnt
# Enable SSH
sudo touch /mnt/ssh

Create a file /mnt/wpa_supplicant.conf, with the contents:

country=<2 letter country code here>
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev

    ssid="wifi ssid here"
    psk="wifi password here"

Set up your user:

# replace username and password below
echo username:(echo 'password' | openssl passwd -6 -stdin) | sudo tee /mnt/userconf

Optional: Set up a hostname.

umount /mnt
mount /dev/sdX2 /mnt
# replace host below
echo host | sudo tee /mnt/etc/hostname

Also edit /etc/hosts so points to your new hostname.

Otherwise, just sync && umount /mnt and you are done.

If you did set up the hostname, and you have .local domains with Avahi set up, you should be able to ssh username@host.local. If you didn’t, or if that doesn’t work, use your router’s DHCP page to find the IP address for the Raspberry Pi.