• Passwords: This is an obvious one!   Make sure all devices connecting to your network have appropriate passwords set.    The longer the passwords are the better.    Also avoid using passwords across multiple devices and/or web services.
• Network Devices: Any accessible devices such as Wi-Fi printers, network web cams, etc. represent a possible intrusion point.    It is therefore very important that you check the default settings for devices, especially in relation to the security settings and also any default access passwords, which you should immediately change.
• Wi-Fi SSID: Make sure your SSID doesn’t give any info away about your router.   By default the SSIDs are usually something like SKY35735 or DlinkWD501 or similar giving hackers a starting point in that they now know the make and possibly the model of the device they are seeking to compromise.    As such it makes sense to change the default password when initially setting up your router.
• Router Admin Password: The default admin password and username are often set to simply “admin”.  This means once in, a malicious actor can easily take admin control of the router and leave themselves a permanent back door to your network, resources and data.    Another key tip therefore is to change the admin password or both the username and password.
• Web Admin: By default web admin is usually enabled meaning a user can access the administrative interface of the router via Wi-Fi.    Disabling this means that to access the admin interface a user would need to be physically connected your home network or router thereby reducing the possible access and the associated risk.
• Wi-Fi Security: Make sure that you have either WPA or preferably WPA2 enabled in your Wi-Fi security settings.   This is all the more important if you have an older router which may still be using WEP or even worse a router where the default is set to Open and therefore no security is applied.

The above are just a couple of tips, of which many more could be added specific to different types of devices, operating systems, manufacturers, etc.    Hopefully the above represents a useful starting point.