Local network configuration begins with a good IP addressing plan! Always try to follow the RFC1918 reserved address space (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) for local networks, using private IP addresses. In this way, you avoid future issues with local addresses overlapping with public addresses on the internet. I have seen many times network administrators not paying attention to this rule of thumb and creating problems for themselves.

Another good practice is not using huge broadcast domains. If you are projecting a small network, then why use a 10.0.0.0/8 network? Avoid doing that! This can save you time in the future; for example, while connecting two or more networks using a VPN tunnel, there will be a smaller chance of network addresses overlapping with other connected networks. If you choose 10.10.10.0/24, which means 254 usable IP addresses, instead of choosing 10.0.0.0/8, which has more than 16 million IP addresses, which one do...