Mostly, you should research device features, but manufacturer of router is important too. As example, here is the most popular: ASUS, D-link, HP, TP-LINK.
There are 4 wireless networking standarts. Recommend you to buy router with standart better than 802.11 n.
Maximal speed of connection
Pay attention on you wireless maximal speed of wireless connection. Router with max max speed of connection equals 30 will limit your Internet connection with speed equals 60.
Range of wireless connection
That feature specify radius of wireless network. This figure is abstract, because in calculation of it, obstacles aren’t considered.
Number of antennas
Speed of data sharing depends on number of antennas. Large count allows router to work correctly without speed decrease, when there more than 1 devices are connected.
Max number of antennas is 6. Router with 6 antennas works very fast and high qualified.
Don’t forget to pay attention that antennas are removable. It will be useful if you want to change old antennas on more powerful.
If you don’t want to share your Wi-Fi network with unknown persons, it’s necessary to have router with data encryption. There 2 methods of encryption – WPA and WEP. Usually routers can use both, but best variant is WPA.
If your router has USB Interface, you can connect devices like hard disc or flash to share it with other users by network. Moreover, you can connect printer or 3G modem (if this function is available).
3G modem connecting
If your router has USB interface, it isn’t mean that you can use 3G modem, because router should has special function for this. You can share 3G Internet to multiple devices by using this feature. This variant is good choose for people who haven’t able to connect stationary provider.
If you have ADSL connection, it’s necessary to buy router which supports ADSL connection. Moreover, your router will work as ADSL and Wi-Fi router at the same time.
Number of switch ports
This feature is one of the most important. Mostly, there are 4 Ethernet ports, which you can use to make wired network. Portable devices can be connected to the Internet by Wi-Fi connection and large devices by cables. All this devices would be in one LAN, but methods of connection are different.
Simple of configuring by using web interface
Some routers have uncomfortable web-interface, which you can enter by typing 192.168.1.1 (in mostly cases), and it’s really hard to add some changes.
Ethernet connection are faster than Wi-Fi, so better try to connect devices to Ethernet, if you can.