Using autonegotiation to your advantage is as easy as remembering one simple rule:
Make sure that both sides of the link are configured the same way.
If one side of the link is set to autonegotiation, make sure the other side is also set to autonegotiation. If one side is set to 100/full, make sure the other side is also set to 100/full.
Be careful about using 10/full, as full duplex is not supported on all 10Base-T Ethernet devices.
Gigabit Ethernet uses a substantially more robust autonegotiation mechanism than the one described in this chapter. Gigabit Ethernet should thus always be set to autonegotiation, unless there is a compelling reason not to do so (such as an interface that will not properly negotiate). Even then, this should be considered a temporary workaround until the misbehaving part can be replaced.