Wireless-N is rapidly overtaking G as the the standard for new implementations.  802.11N offers higher speed, better security and longer range.  Tips for a successful wireless-N implementation:

Buy the right equipment.  An inexpensive AP from Staples may be fine for home or small office, but for anything over 5 users it is worth purchasing a solid access point.  We favor equipment that can run dd-wrt for low to mid range installations, and Ruckus or Cisco gear for large campuses or high throughput requirements.

Stick to 802.11N.  While almost any AP on the market will work with A/B/G, the savings are not worth the performance hit.  If you have older devices that don’t speak N, keep your old gear and add a new wireless-N AP to the mix.

Use WPA2/AES.  At this time, no other encryption works with 802.11N.

Review how antennas work.  High gain antennas have a much different coverage profile than the standard antennas that come with most APs; in some cases larger antennas will make your coverage worse.

Survey the area to be covered; take note of brick or concrete walls; large metal file cabinets and equipment that emits interference.

Use a free WiFi Analyzer.  You can download and use WiFi Analyzer for Android on your smartphone.  Walk around the office, and take note of which channels are in use by your neighbors.  If everyone is using channel 6, switch to 1 or 11.

Location, location, location.  If you have a small space and are using a standard AP with the manufactures’ antennas,  place your access point in a central location.  Remember that this equipment in a circular pattern.  Place the AP at roughly the same level as the equipment that will be receiving the signal.

Consider a USB Adapter. If you are using a WiFi adapter on a desktop, review whether a USB extension and raising the receiver off the floor would enhance your signal.  By the same token, not all laptops have good quality antennas; sometimes it is worthwhile to add a good quality USB WiFi receiver to a laptop or netbook.