- Use the same SSID, encryption type and shared key as your primary wireless router so that you can roam between the APs transparently.
- Use a different channel on your secondary AP if it is in range of the primary no matter how weak the signal is so that you have less interference between your own APs. If possible, use channels as far a part as possible (e.g. 1 and 11).
- Disable the WAN settings. Optionally, turn the WAN port into a LAN port.
- Disable the DHCP services.
- Set the IP of the WAP to a static IP. Remember that it has to be unique and be in the same subnet as the rest of your network (no reason to use a separate subnet unless you have lots of networked devices or special network zoning/security requirements). [TIP: set your DHCP server on your primary wireless router to allocate IPs in a range say 100 - 254. Then you can safely use the IPs from 2 -99 assuming that 1 is already used by your primary wireless router.]
- Set the gateway IP to that of your primary wireless router.
- Set the DNS IP to that of your primary wireless router or your ISP's DNS servers.
- Change the router mode from gateway to router since you no longer need NAT, Firewall and port forwarding services. (can save some CPU cycles and device memory from doing so)
Note that the above tips are only valid if your secondary AP is backed by a wired network. i.e. It is connected to the primary wireless router either via direct Ethernet cables (LAN to LAN port and do use a crossover cable if your ports do not have auto-MDIX feature) or via HomePlugs.
Another way of hooking up the access points is via Wireless Distribution System aka WDS. In this approach, the secondary AP acts as both a wireless repeater for the primary AP as well as an AP for wireless clients (i.e. your laptop).
WDS is cheaper to implement and less messy as it does not require a wired backbone. But do note that your network throughput will generally be halved, latency will increase slightly and the placement of the secondary AP is restricted to locations in range of the primary AP. And lastly, to use this approach, you will most likely need to use a wireless device capable of flashing to third party firmwares like Tomato, DD-WRT or OpenWRT.