Use only one media type if possible. Consult the manufacturer of your network operating system on recommended devices and makes. Don't just grab anything cheap and easy. There are limitations to network size and span. Observe open systems standards when designing and building your network.
Most problems result from an over-expanded network.
Allow for expansion when planning a network. Many new developments take place daily. Don't miss out. Subscribe to and regularly read leading publications. Keep a reminder around so you don't forget.