What are some ways to extend the range of your Wi-Fi?

Repositioning your router or access point minimizes signal obstructions and interference from brick walls, microwave ovens and cordless phones.
Use an Ethernet cable to connect another router or access point to your network to extend its range. Businesses and large residences require more than one access point for the network to reach all users within the building.
Add a bi-directional Wi-Fi signal amplifier or booster to your router or access point's antenna. The amplifier boosts the signal in both the transmit and receive directions, widening its range.
You can connect a repeater between the router and computer to reflect the signal to areas where wireless reception is poor. Clients too far from the router can access the wireless network through the repeater.
Most wireless routers and adapters that have external antennas come with omni-directional antennas. Replacing these antennas with powerful ones that concentrate the signal in a specific direction can help increase the Wi-Fi range.
You may also need to upgrade wireless adapters and internal network cards of your old computers to improve signal reception.